Sciences : histoire orale

WHITTINGHAM Stanley, 2000-10-30

Sophie Jourdin — 2011-11-11T22:33:28Z

Michael Stanley Whittingham is one of the main figures in the history of rechargeable batteries. From the late 1960s until now he has examined promising materials for use as cathode, anode, or electrolyte. He pioneered the use of titanium disulfide for cathodes, now commonly used. He also initiated the concept of intercalation. This term refers to the insertion of positively charged ions into the cathode material. In a rechargeable battery, Li+ ions are typically inserted between layers of the titanium disulfide cathode while the battery is being charged, and then de-intercalated during discharge. That the process of intercalation and de-intercalation of ions leaves the basic structure of the host material intact, so that the charge and discharge can take place repeatedly, was an understanding forged in the 1970s and early 1980s, and in which Whittingham played an important role. He has also been prominent in the field through the editing of its main journal, Solid State Ionics, from its inception in 1981.

Whittingham went into management for a number of years (1984-1988), while the field forged ahead. Japanese companies, in particular, made great strides in the commercialization of lithium titanium disulfide rechargeable batteries. When he rejoined battery research, the Japanese lead was becoming dominant, embodied in a raft of patents.

Since 1988, Whittingham has explored further materials with a view to improving batteries still further, both with regard to size and to performance. This will not change drastically the way in which the energy economy is currently organized (for example, the electrical vehicle is not around the corner), but smaller and more powerful batteries will impact upon the cost and design of portable electronics.

Biographie détaillée

STANLEY WHITTINGHAM (SW) : I graduated with a PhD in solid-state chemistry (from Oxford).

BERNADETTE BENSAUDE-VINCENT (BBV) : So you were trained as a chemist, mainly ?

SW : Yes.

BBV : And why did you go to Stanford, with Prof. Huggins ?

SW : Because in my time almost everyone from Oxford came to the States for one or two years. That was expected if you wanted an academic or an industrial job. It changed a lot... 1968. And why Stanford ? It was on the West Coast, California had sun.

BBV : And your PhD was on tungsten bronzes ?

SW : That's right : tungsten oxides and tungsten bronzes.

BBV : And how did you choose this topic ? It was not that popular ?

SW : No, I think Oxford always had a very active program in solid state. There were three or four faculty there interested in solid-state.

BBV : Who was that ?

SW : Peter Dickins was my advisor ; and J. S. Anderson was head of the department. And Jack Lunette was also there, and he was interested in the theory of calxes. So initially we were studying (?) catalytic activity, and how all that changed with the changes in the electronic properties of the material. There was a great deal of interest in the crystal structure, or rather the band structure, that controls the catalytical activity.

BBV : So it was mainly for catalysis in Britain ?

SW : Right. And we chose a very, very simple reactant : mainly oxygen atoms, and we just looked at how they recombine at the surface. And this was at the time of Sputnik and the US Air Force paid for the research.

BBV : Even the research conducted in Oxford ?

SW : They paid through their London office. Because they were interested in how various species (?) reacted outside their space ships.

BBV : So it makes sense in fact.

SW : Right. And that was the topic of my masters degree mainly. And then we looked at the same materials as catalysts potentially for gas production. And the Gas Council paid for that research. But within a few months of me starting the research, they struck natural gas in the North Sea.

BBV : And you stopped the project ?

SW : No, they said : we are not really interested in what you are doing anymore, but you have got the money. Do what you want and don't bother us too much.

BBV : And in those days money was easy to get ?

SW : Oh yes, you turned down money in those days.

ARNE HESSENBRUCH (AH) : You mean this was the case between the oil crisis and the discovery of natural gas in the North Sea ?

SW : No, they discovered gas in the North Sea before the 1973 oil crisis.

AH : Why did the money flow easily ?

SW : Well, the money came from the Gas Council and they made gas basically from coal. So they wanted a better catalyst to convert. Natural gas avoids all that messy stuff. The rest is really history. London cleaned itself up because they stopped burning coal.

BBV : And then, when you moved to Stanford who was there ? And how was the lab ?

SW : I worked for Bob Huggins there. And that was quite a switch. In England, France, and Germany, solid-state chemistry was a respectable subject. Chemistry departments did solid-state chemistry. In the US you could count the number of solid-state chemists on the fingers of one hand. So I went to a materials science department, not to a chemistry department.

BBV : Was Huggins considered a solid-state chemist ?

SW : He was a materials scientist with a PhD form MIT and he set up a new centre for materials research at Stanford. His interest was in solid-state electric chemistry ; how ions move in solids and things like that. And at that time the Ford Motor Company had just discovered that sodium ions move very fast in a material called beta-alumina. Sodium ions move almost as fast in that solid as they do in a liquid.

BBV : So it was the time of the beta-alumina ?

SW : Yes. Ford published their data in 1967, and I went to Stanford in 1968.

BBV : Did you continue your research on tungsten bronzes there ?

SW : Yes and no. I measured the conductivity of beta-alumina. That is what we tried to do. We has to have electrodes that were reversible to electrons, so we could get a current, and to the ions that were moving. So we paid attention to bronzes that had sodium in them, to metallic conductors, to see if they would make good electrodes. So we have narrowed the Oxford work into the Stanford work.

BBV : And how did you develop the batteries using tungsten bronzes.

SW : I arrived at Stanford in February. In May or June of that year Bob Huggins left to go to Washington to run this whole suite of advanced research centres of materials (?) of which MIT is the last surviving. So he went there and manned those for about two and a bit years. I remained at Stanford and continued my research on the basics. And about the same time, there were others in the medical field who were interested in batteries for pace makers and things like that and there was a number of good silver iodide conductors... (?). And it struck us that sodium or potassium had an advantage over silver because they yield a bigger current. And that is where we got the interest in actually using them. Beta-alumina as the electrolyte and we thought of sodium and some oxides as the electrodes.

BBV : And how did you come to your favourite, titanium disulfide ?

SW : Ah, that is a jump.

BBV : Yes, because you took the patent out in 1973.

SW : Right. While I was at Stanford a number of other people, in particular Hector Ball, who was Professor of Applied Physics and associated with the Materials Department. He was contacted to find people to go to Exxon who were starting up a new corporate research lab. Exxon really had very few chemists and physicists at the time. So I did an interview at Exxon and one at Cornell, and I was offered a job in the Materials Science Department at Cornell, not the Chemistry Department. About a third or a half of the faculty in Materials Science Departments in the US are physicists and chemiusts... they have PhDs in physics or chemistry, not in materials science.

BBV : Incidentally, do you think that physicists have had an impact on your field ?

SW : Oh yes. At Exxon they made me a very nice offer. What they had built up was an interdisciplinary group. It was led by Fred Gamble, who had also come from Stanford. His interest was in superconductivity. And that was the first wave of superconductivity. What we tried to do then was to look at (?) tantalum disulfides. And by intercalating different molecules between the sheets of tantalum disulfide we could change the superconductivity transition temperature. So, tantalum sulfide became superconducting, I think it was at 0.8 degrees Kelvin. By putting in different molecules you could raise it to about 6 Kelvin. It turns out that the one that could raise it the highest was potassium hydroxide. And my first job was to try to understand what was going on. And what I found out was that basically potassium ion structure was particularly stable in TaS2-... It behaved like a salt ... there was again of energy ... (?).

AH : Where was this new Exxon lab placed ?

SW : It was across the street from a refinery in Linden, New Jersey, along with a raft of other chemical and solids research labs. Basic research. And the goal was to be prepared since oil was soon going to run out. My part was energy-related systems, other than petroleum and chemicals.

AH : It was set up in 1972 and you were there from the very beginning ?

SW : It may have been set up in 1971, but basically yes.

BBV : How many people worked with you on this project ?

SW : The group headed by Fred Gamble : there was about six of us. Each one of us had a different background. Fred Gamble himself was something like a physical chemist, there was an organic chemist, some were physicists.

AH : Presumably you had plenty of funding for equipment and the like ?

SW : In those days, if you needed something for your research you asked for it, and it would be there in a week. Money was no issue. They invested in a research laboratory like they invested in drilling oil. You expect one out of five to pay off.

BBV : Was it perceived as a long-term project ?

SW : Yes.

BBV : And what did that mean : 10 years ?

SW : 5-10 years. Industry has changed considerably since then. I would say after about 7 years they began to ask : well, what is going to come out of this ? By that point we had moved from tantalum sulfide, which is really no superconductivity material. We were looking at lighter materials : titanium sulfide. And we were looking at lithium, not potassium, because it turns out that potassium is very dangerous. And some time in this period a Japanese company had come out with a carbon fluoride battery which they used for fish floats. They fish at night and they need to see where their floats are. And that was a primary battery. This was the beginning of interest in lithium batteries.

BBV : So the initial interest came from Japan ?

SW : Well... we thought we could do something better. It was a high-voltage, one-shot, then you throw it away. And Exxon was only interested in rechargeable systems. They were looking to the electrical vehicle.

BBV : From the very beginning ?

SW : As soon as we started. We were only in energy, but we told them that we may have a battery and they immediately jumped to the notion of an electrical vehicle. And they in fact built – well it must have been in the mid-1970s – a 3W and diesel hybrid vehicle running on the roads.

AH : Presumably the Japanese were also interested in the EV at this early stage ?

SW : No, they were not interested at all. In the mid-1970s some Japanese companies started selling calculators with solar systems built in.

AH : In other words, they focused only on smaller batteries than those employed for vehicles ?

SW : Yes. And it is important to make the point that no battery company came up with any inventions. Every invention coming from Japan came not from a battery company. They had a device they wanted to take to the market. Sony, Sanyo. It is a straight busines. They do not stray from where they have been.

BBV : And from where did you get your techniques in intercalation chemistry ? Did you receive training in this already in Oxford ?

SW : Well, the tungsten bronzes are quite similar in this respect sodium, lithium, or hydrogen in and out. There was interest in electrochromic displays in the late 1960s early 1970s and so we were all familiar with them. You have tungsten dioxide and you put in in acid adding a bit of zinc. It generates atomic hydrogen and turns into a solid going from yellow to blue.

BBV : Yes, but when the mixed conductors started, I think there was something of a change in intercalation chemistry.

SW : Yes.

BBV : Was there any feedback from your research at Exxon to intercalation chemistry ? Or was it isolated as a completely industrial research lab ?

SW : No, I think we had a huge impact. At the time Bell Labs were doing similar things. They were located close to us, they were a similar group, also with many individuals from Stanford. We were competing head-on for a while, also in publications. If you look at our publications on the battery, you will see a lot of basic science with no mention of batteries at all. Exxon clearly did not want to disturb their aura (?).

AH : What journals did you publish in ?

SW : Electrochemical Society, Materials Research Bulletin. But the electrochemical stuff came after the basic stuff. So much of the basic stuff went into the MRB which had a very strong reputation in those days.

BBV : So, you have been working on titanium sulfide for many years ?

SW : I started working on that when I joined Exxon in 1972, already in October. As soon as we started work on it we realized that it had very interesting physical properties. So my colleagues like Art Thompson ... (?). After a year we knew about that material than anybody in the world.

AH : May I ask a couple of questions about the early period before we get advance too far chronologically ? Would you please contrast the appearance of the labs at Oxford, Stanford and Exxon ?

SW : Sure. Oxford was an organic chemistry lab. We were in the old wing of the building, built probaly at the beginning of the last century. The walls are three feet thick. There was mercury all over the floor and under the floorboards. It was an antique place. But most of the facilities were there. It was all set up for solid-state work, because the head of the department was a solid-state chemist. We had some of the first NMR ... (?). It was, I would not say state of the art but, pretty good for those days. And what people don't realize is that there was no such thing as an electronic calculator. The computer we used took up a whole Victorian house and it had less power than one of those [pointing to a PC].

AH : What was your working day like ?

SW : If you were running an experiment you stayed there. There was no computer. If you were lucky you had a chart recorder. change temperatures... (?) You built your own equipment, you could not buy it.

BBV : Was the equipment different in Stanford ? Was it a shock ?

SW : Stanford was a new building. The Center for Materials Science had been built just a few years earlier. The building was new, most of the equipment was fairly new, though soime of it was surplus from (?). But the change was more going from a chemistry department to one of materials science. There were no fume hoods in the buildings. It was much more electronically oriented and obviuously the computers at Stanford were then better than those at Oxford. And after maybe a year there, a hand-held calculator costing about $95 came out. ..... (?)

BBV : And that was important for your own field ?

SW : Yes, because we wanted to measure how fast ions move. We made the first measurements over the first 5 or 10 seconds. You can do it with a chart recorder but it is very difficult.

BBV : And at Exxon ? Did you have everything you needed ?

SW : You had everything you wanted within reason. It was a new set-up and wanted to get it going right. Their attitude was that our time was much more expensive than the equipment.

AH : Were there more technicians at Exxon than the other two places ?

SW : No, I would say it was almost the opposite. Oxford had more support staff than any place in the US. We had a huge machine shop, a huge glass-blowing shop. And you had the old business of artisans in what were called shops. They would do new things for you, but they expected you to do anything routine by yourself. If it was complicated, they would do it for you.

AH : And in the US you would buy in ?

SW : Yes, there you tended to buy stuff. There was some support staff but nowhere near the same. These days there is almost no support staff.

AH : But the impact of the computer has generally speaking been more marked in later periods than the one we are talking about now, right ?

SW : Yes, when did the PC arrive ?

AH : I think it was about 1986.

SW : And I was at Exxon from 1972 to 1984. We came up with a battery patent early on. We had an incredibly good patent attorney. They would write up your invention and then ask you : why can't you do it this or that way ? And they came up with ideas for building a battery fully charged or fully discharged. TiS2 patent... (?)

BBV : And did you publish more patents or more articles during your time at Exxon ?

SW : More articles because one of the goals was to get Exxon better known as a research institution so they could hire better scientists. And there was some pride with the president of the company that he wanted to compete against Bell Labs. So he wanted us to be perceived as the labs of the energy business. One of the presidents was E.B. David (?) who subsequently became head of the board of Science Advisors or something like that. He wanted Exxon to be known as the best place in the world.

BBV : So they valued research over patents ?

SW : Both.

BBV : Was not there a tension between the two in the disclosure of results ?

SW : Yes. The publications did not mention batteries at all. So we made materials and we described how we made them. We then discussed their scientific behaviour, how they reacted with water, their thermodynamics. But anyone smart enough would know what we were doing. They soon caught on. And I think about 1975 or 1976 when the first patent started coming out we released the first paper in Science Magazine. And about the same time we also published ... (?). Because up to that time people in the battery business did not know what intercalation was. ...

BBV : Did you attend the Belgirate, Italy, meeting in 1973 that purportedly is the founding event of the community ?

SW : Yes, I gave two papers both of which went very well. And the other thing I remember is that Carl Wagner attended that meeting. He was very old. He basically put the field of corrosion on a scientific basis. He ought to have received a Nobel Prize.

BBV : Were there more Europeans there ?

SW : It was organized by Europeans, and I think there were more Europeans. And I remember that I was there with my wife and two young children. We bailed out half a day early because they said it was going to snow in the Alps, in order to go back to England.

AH : Were there any Japanese present ?

SW : Yes, I think there were a few.

AH : So you agree with the interpretation that this was a founding meeting ?

SW : Yes.

AH : One might also point to the beginning of the journal Solid State Ionics (1980) as the origin of a community ?

SW : Yes, but by that stage we were already having annual meetings.

BBV : Did the journal make any difference ?

SW : Do you want a bit of history of the journal ? The North Holland folks then had an office in the US. I lived in New Jersey two miles away from the publishing editor. They published the Belgirate proceedings. And this editor said : we need a journal in this field. I was one of those who said : no we don't.

AH : Why did you think that ?

SW : I thought there were too many journals already, even at that time. There were few compared with today of course, but even so. So he said, you prove that to us and we will pay you to do it. So Hans Becker (?) and I sent out a mail to everyone in the community, saying North Holland was going to start this journal and was there any interest ? I fully expected to get negative feedback hbut 95% wanted it. So North Holland played every nice game and we could not say no.

AH : Did the journal then not change anything much ?

SW : Yes, the journal changed a great deal because it pulled all the papers together in one place. Remember in those days there were no journals such as Chemistry and Materials. Solid-state chemistry had just started and that was more high-temperature. And there was the Materials Research Bulletin. So papers were all over the place. So they convinced us to go with it. I had my arm twisted to edit it. Within one year we went from single-column to double-column format and larger-size paper. It basically took off straightaway.

BBV : The whole community decided to publish in this journal instead of in the others you mentioned ?

SW : Yes. They kept publishing in other journals also, but they knew that here they would have their stuff recognized .

BBV : Was it a fast publication ?

SW : Five months. The goal was to get it out quickly. In those days the Materials Research Bulletin got things out in two months.

BBV : Let us come back to your career. Why did you leave Exxon in 1984 ?

SW : Exxon had one good thing about them. It was run by scientists and engineers, not by lawyers or MBAs. I will give you an example. When we had come up with the battery, the board of directors came to the lab to listen to us. And they then said here is the money, now go and do it. So they built an applied film group costing millions of dollars, a very good one. It was like a poker game : well we make a big dollar or we loose it. Their philosophy was that if you were a good scientist then you would also be a good director. So within a few years I became a lab director. I am not sure exactly when but at some stage they said : now you have shown that you can manage something you know, so we will now send you off to manage something you do not understand. That is why I went to an engineering facility, where I headed their chemical engineering. I was responsible for technology, for synthetic fuels in those days, chemical plants, raffineries. It sounded challenging at the time and I stayed there four years. At that time began the shale oil and coal gasification (?). It was a booming period. My job was to employ as many chemical engineers as I could lay my hands on. But soon the writing was on the wall and the slump was coming. We started laying off people. We went from roary-rosy days to (?). And I was doing no science myself then. I missed that and that is why I went to Schlumberger. My first boss at Exxon went to the Metallurgical division there.

BBV : What kind of research did you do there ?

AH : It was 1984-1988.

SW : Right. Schlumberger was in Richfield, CT, the lab was built and designed by a famous architect called Johnson, from Texas. One or two stories, glass, a very pretty building. You could not have your names on the doors or pictures on the walls unless they'd approve them. Schlumberger was then the Rolls-Royce of the oil field. They built very expensive analytical equipment which they put down oil wells to determine whether there was in fact any oil down there, what the rock foundations were like. They would put these probes worth millions of dollars down the well, pull them up very slowly and you would get wiggles and charts and things like that. And if they could reproduce the wiggles they would sell it. It was a very low-key company. In those days they probably made more money than all but two or three of the biggest oil companies. What they did not have was chemists, those who tried to understand what these measurements actually meant. They did have a large number of physicists and electrical engineers building the instruments. Then they decided to build up a basic rock science group, the job of which was to try to understand what was measured. And I went as head of the group, to bild up the chemistry activity with the engineers. One of the biggest electrolytes in the world is clay. It is clay in the formations that causes various forces to be formed in the earth and you can measure them.

AH : So you were not really moving to something completely new. This is the link to your previous field.

SW : Yes, but I had been doing management. At Schlumberger I was dealing with chemical engineers. But as my wife said, I was doing far too much travel. Schlumberger had labs in Texas, Connecticutt, Tokyo, Paris, and Cambridge, England. During my first year I was in the US maybe half of the time.

BBV : Is that why you stayed only four years there ?

SW : When I went there it was a booming organization run by a Frenchman (Ludeau ?). A whole book has been written about him. He died, and his chosen successor failed. There was a palace revolution. And a Scotsman was in charge, Ewan Baird (?), I think he is still in charge. At that point they were building a new chemistry facility in Richfield. They had put the foundations in, and he came in one day and said, no. Construction stopped. He ordered people back to basics. Schlumberger also had some TV stations back in France. They invested in other things. It was as if they only wanted to have Nobel Prize scientists : only the best was good enough. They did hire some outstandingly strong theoretical physicists. We looked at how oil flows through sandstone in rocks. Sprinkering (?) techniques ..very similar to how snowflakes build up on the window. Some people there did not like it : why are you doing this ? There was a reaction against basic science and people wanted to get back to building and improving equipment.

AH : Was the basic stuff modelling ?

SW : Yes, there was a strong modelling component and a measurement component. At that time we had about 30 people in this basic science group. We were told basically that we could become engineers or leave. We were given about 18 months. They were very generous. Some of the best people were in their 20s. Three of them were offered tenured professorships within a month.

AH : This is also the period of change from the mainframe to the PC.

SW : Yes, and Schlumberger was big on that. They had a Cray computer and Macintoshes. The theorists wrote their programs on the Macs and ran them on the Cray. Schlumberger also had e-mail, around the world. We were in touch with the Japanese and the French. That was really the first time that I used e-mail. They were well ahead.

AH : This must have been towards the end of your time there ?

SW : They had it from the beginning. Remember, they were well versed in how to get electronic information.

BBV : Did you go straight from Schlumberger to SUNY Binghamton ?

SW : Yes. At that time I decided that US industrial research activites had started on a down hill. Exxon had cut back on their basic research by about 50%. Seven years earlier they had doubled basically overnight. Then they had said : what would you do if we gave you twice as much money ? Give us a plan by Monday (that was on Friday). In my recollection we worked all that weekend. Within a week we had the doubled size.

AH : How would you account for the change in atmosphere, for the downturn in the mid-1980s ?

SW : A number of things : 1) oil prices had been going up but then they dropped ; 2) MBAs started getting into the business (short-termism ; now the stock price is more important than everything else) and then they looked hard at basic research. With regard to Exxon : it is a mammooth company. The corporate labs were under $50 million. When they doubled it, it got above $50 million. They rounded everything off into hundreds of millions. Anything under $50 million just did not appear in the balance sheet. 3) When the oil price went down there was no longer a sense of crisis. So you do not need any longer to investigate all the alternative forms of energy. Exxon had gone into solar, batteries, computers, a chip company. But Exxon did not really have the management expertise. At about that time Exxon sold all their battery technologies. They licensed them to a Japanese company, one American and one European. I think it was Sony in Japan. Exxon said : you mean you can not make $100 million a year on this ?

AH : It would seem that the price of oil is a really good indicator of the field of solid-state ionics ?

SW : Yes. When Exxon got out, the whole field got out. The federal government cut funding, thinking that if Exxon was not interested, then why should we be.

BBV : So how did the field continue ? Where did the incentive come from ?

SW : Europe was continuing. The Japanese had our technology. There were a few problems with it. They wanted a safe anode ; they could not use pure lithium. ... (?) John Goodenough came up with cobalt oxide. That is almost double the voltage. Sony combined that with an interpolation compound of graphite as the anode ; and came out with what is called (?). The Japanese now have some 90% of the market for all lithium rechargeables. Sony has the primary licence making sublicenses. I think the patent is running out any day now. A number of companies toyed with getting into the business. Eveready two years ago started a plant and found that they could buy the batteries cheaper in Japan than they could build them themselves. The Japanese just have such a long lead time.

AH : Your personal choice of going back to academia. There was no future in industry you said...

SW : There was no future in industry and I wanted to do my own thing. In the mid-1970s 9 out of 10 solid state chemists were in industry. About that time chemistry departments in this country suddenly realized that this is a field. We want these people. Now, 9 out of 10 are back in academia.

AH : What impact did the return of solid state chemists to academia have upon the field ?

SW : In 1987 superconductivity happened. All solid state chemist jumped on board. The result was this symposium. Meeting in New Orleans. The largest room in New Orleans was not big enough.... [too much noise]

BBV : The field suffered from the cold fusion affair ?

SW : Yes and no.... [too much noise] few people got involved in cold fusion

AH : Characterization ?

SW : Computerization has accelerated the getting of measurement results.

Most of these batteries have maybe one or two years. They last as long as the product itself. As far as environmental concerns : they are pretty darn good. [noise]

AH : Hybrid vehicles ?

SW : They are there. The Japanese have them. All that is needed is the political will to factor in the environmental advantages.

BBV : Oxide markets ?

SW : Electrochromic displays.

AH : Optimism when you started ?

SW : Optimism fuelled by end of oil. Now the end of oil is not in sight. But batteries are needed in the small electronic devices. The EV is not everything.

AH : Whom should we talk to : Frank, John Goodenough, Michel Armand.

BBV : Hagenmuller ? Steele ?

SW : Steele is still active.

AH : Fuel cell relevance ?

SW : Fuel cells are much more active in Europe than in the US.

AH : For political reasons ?

SW : No, .. [noise]

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« Entretien avec Michael Stanley Whittingham », par Bernadette Bensaude-Vincent et Arne Hessenbruch, 30 octobre 2000 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article132.

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Entretien avec Michael Stanley Wittingham, par Bernadette Bensaude-Vincent et Arne Hessenbruch, 30 octobre 2000

Lieu : SUNY Binghamton

Support : enregistrement sur cassette

Transcription : Bernadette Bensaude-Vincent et Arne Hessenbruch

Edition en ligne : Sophie Jourdin

HIRSCH Peter, 2002-12-12

Sophie Jourdin — 2011-11-04T14:03:56Z

Professor Sir Peter Hirsch.

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BERNADETTE BENSAUDE-VINCENT (BBV) : Could you tell me about how metallurgy developed in Oxford and how it grew into Materials Science ?

PETER HIRSCH (PH) : Let me first say a few words about the way I see the early developments of Materials Science in the UK. There were various trends that came together after the War. First of all there was Professor Nevill Mott in Bristol, developing Solid State Physics. His interests included inter alia defects and how they influence properties of materials. He had important activities on properties related to point defects and on the photographic effect. In the course of these studies they also developed techniques for visualizing dislocations. The group included Charles Frank, a physical chemist by training who was a material scientist par excellence. He developed a theory of crystal growth. Then there was Nabarro who worked on dislocations. So in Bristol they worked on defects, dislocations, crystal growth, the photographic effect, and also optical properties of crystals.

BBV : Where were they based ?

PH : In the Physics department at Bristol University. It was Solid State Physics. The electron theory of metals was developed there too. And Jacques Friedel was there for some time. In my opinion Solid State Physics opened the way to Materials Science. In parallel with this there was the group in the Metallurgy Department in Birmingham, lead by Alan Cottrell. He is much more of a materials scientist than I am. He was subsequently instrumental in developing Materials Science in Cambridge. His activity in Birmingham was very important because his group attempted to explain mechanical properties in terms of disclocation theory. And the third trend was what happened here in Oxford through Hume-Rothery's classic work on electron phases of alloys. He stimulated work on electron theory of metals and alloys in Physics Departments elsewhere. He was trained as a chemist.

BBV : So it came out of these three trends ?

PH : These are the main three. I may be unfair to other groups but these were the most influential groups.
There was some Metal Physics going on in the Cavendish Laboratory after the war. Bragg, who was Head of Department was of course an X-Ray crystallographer. In order to understand the intensities of diffraction spots on an X-Ray diffraction photograph, it had to be assumed that the crystals were not perfect, i.e. that crystals consisted of mosaic blocks. This was based on a theory by Darwin (1914) of the intensities of diffracted X Rays. Bragg published a note in the 1940s on the relationship between strength and particle size (mosaic blocks) in crystals. There were two groups in the Cavendish in the Metal Physics field when I came in 1946. One was Bragg's little group which developed the bubble-model, typical of Bragg's simple but brilliant ideas. Another group was Orowan's Metal Physics group which studied plasticity, fracture, creep, those sorts of topics.

BBV : It is in the Cavendish Laboratory that you started your career, isn't ?

PH : It was 1946 when I joined and there were several activities. My own work started from Bragg's interest in work hardening (when you deform a metal it becomes stronger). I actually went into the Crystallography Department of the Cavendish to work on a PhD problem that Bragg gave me. It was conceptually very simple. If you take a metal and work it, does it break up into smaller blocks ? Bragg always had very simple and brilliant ideas. If the crystal breaks up into smaller blocks (subgrains) the diffraction pattern consists of individual spots from each little subgrain. If you make the beam small enough you illuminate such a small number that you will get a few spots on the diffraction ring, whereas, with too large a beam diameter you get a continuous ring due to overlapping spots. You can count the spots (on discontinuous rings) and deduce the size of the particles. That was the project. It did actually work for heavily cold worked aluminium. We derived a particle size of 2 microns. By the time we managed to do all this by X ray diffraction, Bragg had lost interest in it. He did not actually supervise me. Bragg was interested in proteins at that point. My formal supervisor was W.H. Taylor who was head of the Crystallography Department. His interest was the structure of minerals.

BBV : When you worked in Cambridge did you consider yourself as a crystallographer ?

PH : I was a physicist working in a department of crystallography. In those days most conventional crystallographers determined crystal structures. I was one of the relatively few people not doing that.
By the time we found that cold worked aluminium breaks into subgrains, Heidenreich at the Bell Laboratories published the first pictures of metals by Transmission Electron Microscopy (TEM). He observed directly the little subgrains in heavily beaten aluminium foil. That depressed us very much because we needed exposures of many hours for our x-ray diffraction photographs, while he had a ten second exposure with his electron microscope. So we went into this field of TEM and finally we saw individual dislocations. This had a big impact because there were many metallurgists who did not believe in dislocations, who considered them as figments of the imagination of solid state physicists working out theories in tremendous detail without much supporting experimental evidence. With our technique you could see dislocations directly and see them move. And we made movies. I remember showing a movie at MIT to Bert Warren who was a well-known X Ray crystallographer. His comment was symptomatic of many metallurgists. Seing is believing. We converted people.

BBV : In terms of institutions could you describe the shift from Metallurgy to Materials departments ?

PH : There were many Metallurgy departments in this country : Sheffield, Birmingham, Imperial College, to mention a few. The activities of the groups that I mentioned gave an impetus. But an important impetus came from the United States. Bill Baker and Herbert Holloman in particular had this vision of multidisciplinary activities leading to the development of better materials, whiskers, ceramics etc.. An enormous amount of money was spent at General Electric, and Bell Telephone and the Ford Motor Company. When Alan Cottrell became Professor in Cambridge that was the real beginning of an institutional effort to develop Materials Science in this country. In my opinion that was the defining moment. Alan Cottrell left Birmingham in 1955 and went to work at the Atomic Energy Authority at Harwell where he worked on uranium and materials for nuclear reactors. Then he became Goldsmith Professor of Metallurgy in Cambridge in 1958. He started projects on ceramics and composite materials. Tony Kelly joined him to work in these areas. Alan Cottrell ‘s interest in composite materials probably stemmed partly from activities in the US but mainly from his own views on strong materials. He also supported work on superconductors. His initiative to work on different types of materials was probably the beginning of the shift from metallurgy to materials science in Universities in this country.

BBV : Could you tell something about the implementation of Materials Science here in Oxford ?

PH : The department of Metallurgy and an Honour School in Metallurgy were started by the University in 1957. Jack Christian wrote a paper on the early history (Materials World, April1997) when the department celebrated its 40th anniversary. You see from this that Hume-Rothery started as a chemist and worked in the Inorganic Chemistry Department. But he was interested in metallic phases. The idea of a separate department arose gradually. Jack Christian was appointed as demonstrator in 1951 and initially lectured on metallurgical topics to chemists. Metallography was a supplementary subject in the Chemistry Honour School. Then the Pressed Steel Company at Oxford established a readership in metallurgy named after George Kelley. Hume-Rothery became the first George Kelley reader in 1954. Jack Christian was appointed lecturer in 1955, then John Martin came from Cambridge and joined in 1957, followed by Angus Hellawell. There was a move to increase the Engineering School and to develop a Department of Metallurgy. Francis Simon who was professor of physics here was keen to establish something on the lines of the Laboratory for the Study of Metals in Chicago, which was famous in those days. Chicago was a research institute, not a teaching department, just a research institute for postgraduates. This is what Simon had in mind for Oxford. However, the industrial advisors expressed the view that we needed to educate metallurgists to go into industry. British industry wanted a teaching department. Monty Finniston, who was at the time the head of the metallurgy division at AERE Harwell and later became chairman of British Steel, made approaches to the Wolfson Foundation for financial support. The result was the establishement of the Isaac Wolfson Chair in Metallurgy which Hume-Rothery held until his retirement in 1966.
At the same time the condition that the Wolfson foundation made for giving the money for the Chair was that the University Grants Committee, an organization distributing the money from the Department of Education to the Universities, should provide the funds for the building. Funds were provided by the University Grants Committee and the building was opened in 1959. Initially the Honour School was a Joint Honour School in Chemistry and Metallurgy, which subsequently became Metallurgy. There is an interesting quote in Jack Christian's paper which indicates the University's unease with technology at that time. The Honour School should teach « no more technology than is involved in the degree courses of chemistry and physics » and it stated that « the man who has studied pure science at a university can take up technology on entering industry much more easily than one who has studied technology can later take up the pure science which may be required for his work ». It was still quite difficult to really expand engineering and to get a proper engineering metallurgy course at that time. The research that was going on here was on alloy phases (Hume-Rothery's research) ; John Martin worked on mechanical properties of alloys ; Angus Hellawell worked on solidification studies ; Jack Christian worked on phase transformations - the martensitic transformations - of metals and alloys, and also on plastic deformation of body centred cubic metals. So that was the development of metallurgy in Oxford before 1966. Clearly this department was a metallurgy department rather than a materials department. But Hume-Rothery's work was influential in encouraging solid state physicists to become interested in metals. He stimulated the understanding of the structures of metals and alloys on the basis of the fundamental electron theory of metals. He empirically developed some structure rules. He hoped that electron theory of metals would enable the prediction of the structures of metals and alloys and appointed a theoretical chemist, Simon Altmann, to work in this area.

BBV : And then you came in this Metallurgy department. Why did you move from Cambridge to Oxford ?

PH : I came in 1966. I was a physicist who had worked on electron microscopy of defects in materials. I had the opportunity to take a Cambridge chair or an Oxford chair. I decided to go to Oxford for two reasons. 1) I had been in Cambridge quite a long time (23 years) and a change opens new vistas. 2) The challenge was much greater here and my own predilection was always for building things up. The Cambridge Metallurgy department was a large and successful department built up by Alan Cottrell. In Oxford there was really a nucleus of a department (a distinguished one) and in principle one could do a job to build it up.
I had already built up a large research group in the Cavendish in Cambridge. When Bragg switched his interests to proteins (Perutz, Kendrew et al) Orowan left and went to MIT. I don't know the details but my impression is that Bragg did not work hard enough to get Orowan a senior permanent job. So the Metal Physics group in Cambridge folded up. Bragg's own little group folded up too. We made a significant effort to set up a new Metal Physics group at the Cavendish. The vision behind this was : We now had a technique to enable us to actually see with the TEM what is going on inside metals and one could see the defect distribution after deformation or irradiation of the material. One could then determine in principle what the properties of the materials were. That was the Holy Grail. There were three steps : 1) to try to understand the properties of the defects and how they interacted ; 2) to try understand how they control the macroscopic properties ; 3) if one understood the basic relation between defects and properties then one could eventually go further and predict what processing should be done to optimise properties. That was the vision but while we were successful in the first step, there was only limited success in the second step, and we never got as far as the third step.
When I came to Oxford, my aim was to get this technique of TEM - to see what goes on in the materials - transferred to a metallurgy/materials department. I wanted to get it closer to applications to « real » materials. Whereas physicists work on models, - on pure copper for instance, a metallurgy department should be looking at materials of interest technologically, such as alloys that are much closer to practical needs. My aim was to apply TEM to technologically interesting materials, real materials rather than the model materials that we looked at in Cambridge.
When I got here I did attempt to build up Materials Science. Right from the beginning my aim was to shift from metallurgy to materials science which should cover all kinds of materials and applications.

BBV : Where did this project come from ?

PH : There was no model course. We had to build this up incrementally. When I first came the University provided three new permanent posts, very generously. One was for Professor Whelan, to establish the electron microscopy group. One went to John Hunt, a solidification expert who had worked at Harwell and Bell Laboratories ; and another one was for Geoffrey Groves who worked on ceramics. Gradually we built up a Materials Department by securing more appointments. You have to realize that when I came in 1966 the number of staff was very small (4 faculty plus the Professor).The course developed gradually and changed from metallurgy to materials science. In the early years a considerable part of the teaching was carried out by research assistants or fellows supported on research grants or fellowships. The research activities were built up first, and the research groups then helped in the teaching of the Honour School.

BBV : When did you officially change the name of the department ?

PH : That was much later, 1990. The name of the Honour School was changed to Metallurgy and Science of Materials in1969 (The University would not accept "Materials Science" because Materials was not an adjective !).

BBV : Did you appoint chemists as well ?

PH : We didn't appoint chemists to teaching posts. We appointed metallurgists and physicists. But we did appoint a chemist to a research post in the department, in high resolution electron microscopy. When I retired in 1992 the department consisted mainly of metallurgists or materials scientists and physicists or ex-physicists. We appointed inter alia people who had expertise in semiconductors, superconductors, magnetic materials, materials processing, corrosion. Gradually we extended the scope of the courses in the department. The one sticking point was polymers. For a very long time we could not get a good polymer scientist. It has changed now. We now have two polymer scientists.

BBV : Did you have contacts with John Goodenough who came to the chemistry department in 1973 ?

PH : We did have contacts but we probably did not make the best of the opportunity. In this department we were more interested in the effect of microstructure on materials, metals, ceramics, semiconductors, superconductors, magnetic materials etc., rather than e.g. in the intrinsic magnetic properties of perovskites and other materials. Our interests were not sufficiently close. We became a Materials Department in that we were concerned with the effects of microstructure on properties of a wide range of materials of technological interest and with the effects of defects on devices. The work on superconductors was initially on low temperature superconductors, but later on high temperature superconductors, and the more recent studies focused on processing. There was some interaction with the Inorganic Chemistry Laboratory on electron microscopy of catalysts and superconductors.

BBV : Did you keep a close link between courses and research in the department ?

PH : Yes. We started as a metallurgy department. We built up a number of research groups, and the expertise in some of these, e.g. semiconductor and magnetic materials, enabled us to teach courses on these topics and broaden the curriculum to Materials Science. At some point we had a group working on cements, and this too led to a course in the Honour School. And there were always undergraduate and postgraduate courses on materials characterisation, where we had particular strengths. In the 1980s, I became more interested in the output end, in getting closer to the engineers.

BBV : Did you train students in engineering ?

PH : The engineers had their own faculty to teach materials to Engineers. But we did some teaching for them, and over some years they taught polymers for us. In the mid 1980s we started a joint course with the Engineers on Electronic and Structural Materials Engineering, changed to Engineering and Materials in 1992. This led to closer collaboration with the Engineers in teaching and research.

BBV : Did you also have contacts with the nuclear physics department in Oxford ?

PH : The only contact we had with the Nuclear Physics Laboratory in Oxford was on their proton microprobe, a materials characterisation tool, and fairly recently this activity was transferred to our department.

We had a lot of contacts with Harwell. From 1973 onwards I got very much involved with the study of the integrity of pressurized water reactors through the Marshall Committee. From 1982 to 1984 I became part-time chairman of the Atomic Energy Authority. This period had a strong influence on me. I felt the need to produce materials engineers, not only materials scientists. I learned during my period with the Atomic Energy Authority that the education of engineers in materials tended to be relatively poor. And this could result in inappropriate component design or manufacture. These problems sometimes led to costly mistakes. In order to develop a joint activity between engineers and metallurgists we got some support from the engineering department. To cut a long and difficult story short, we took an opportunity which presented itself around that time in the form of additional funding for engineering courses from the Government to start a course on Electronic and Structural Materials Engineering.

BBV : Was it in the 1980s ?

PH : Yes.

BBV : Did you then feel the need to add « engineering » in the name of the department on the lines of the departments in US universities that are called Materials Science and Engineering with an emphasis on the E of Engineering ?

PH : What happened here is that we developed a multiplicity of courses to provide more options for the undergraduates to increase our intake. The courses were Metallurgy and the Science of Materials, then Metallurgy, Economics and Management (1979), and finally Engineering and Materials. There is close collaboration between us and engineering through the teaching and contacts in research. This depends on individual contacts of course. In the 1980s we set up with the Engineers the Oxford Centre for Advanced Materials and Composites (OCAMAC) to foster collaborative research and contacts with industry. There is now also strong collaboration with people in chemistry and physics on a number of research programmes. We have become much more interdisciplinary, if you like. We have always considered ourselves as a bridge between the Science and Engineering Departments, with contacts with both. The fact that Physical Science and Engineering are all part of the same faculty in Oxford is advantageous to us. We did consider changing the name of the Department to Materials Science and Engineering - but that was unacceptable to the Engineers who considered Materials Engineering to be their responsibility. So we decided to change the name in 1990 to "Department of Materials".

BBV : It seems that your story is quite different from that of the US materials departments.

PH : I think that it is different ; you are quite right. Here the initiative to have Materials Departments came from academics, whereas in the US the development was led by Industry, and industrialists promoted Materials Science in Universities. (This does not mean that no materials science was going on in industry in the UK - e.g. the carbon fiber work at Farnborough.) I think it started in Cambridge first. We came along in the late 1960s. By that time there were materials science activities going on in many departments, at Imperial College and Birmingham, for instance. We could not claim to have inspired Materials science in the UK. We came along and did our own brand. There were many departments, but they were on a small scale. Concerning the definition of Materials Science I am with Merton Flemings. Structure, properties, processing, performance/application. I think it is the engineering applications that are fundamental. The philosophy of the department here was to get theoretical and practical people together. People able to develop models with people who really know what applications are important. And industrial links were fostered. It is still the philosophy today, even more so. In the last few years after my retirement the department has gone from strength to strength in that direction. There is now another site in Begbroke, five miles away from Oxford centre. It provides opportunities for collaborative research between the Department and Industry.

BBV : Where did the money come from ?

PH : The funding for work in the department came partly from the University, the Research Council and Industry. Some from charitable foundations, e.g. for building expansions. We had a large budget from the Research Council. That is another important aspect, somewhat similar to the US picture.

It is difficult to attract undergraduates to read Materials Science and Metallurgy. Enormous efforts have been spent on attracting more undergraduates, most of them not very successful. (But a recent appointment of a Schools Liaison Officer seems to be effective.) Materials Science is not a school subject, although elements are introduced into some of the school examination papers e.g. the physics curriculum. The number of courses and options that we offer in Oxford has helped a bit but it remains a problem. Some small departments in the UK were able to survive because they had a large research activity (supported on non-University funds) compared to the undergraduate activities. But in the UK as a whole some Materials Departments have closed or have been amalgamated with Engineering Departments. The change of name of department from Metallurgy to Materials does not only reflect the change in content of the courses. It is also pragmatic because metallurgy has an old-fashion ring about it and materials science is a much broader subject likely to attract more students. The image of materials for computers, aeroplanes and cars is more exciting than that of dirty blast furnaces in the steel industry.

BBV : What would you say about multidisciplinarity in the development of this department ? More specifically could you compare the situation here in Oxford with this diagram published by the National Academy of Science in 1969 with a hard core in mathematics physics and chemistry and applications around ?

PH : I would agree with this : mathematics, physics and chemistry are basic inputs in Materials Science with applications in ceramics, polymers, and so on. But in these days I would include materials for medical applications. There is somebody in this department working on biomedical materials for implants. There is also a large group in Cambridge. There is a big scope for materials in medicine, particularly for prostheses.

BBV : Finally would you consider yourself today more as a physicist or as a material scientist ?

PH : I think I am physicist who « saw the light ». True physicists would no longer consider me as a physicist. I consider myself as a materials scientist because my interest is in the effect of microstructure on the properties of materials. I am interested in quite complex materials, with potential applications e.g. high temperature intermetallics, and in modelling their complex mechanical properties. I ended up as a materials scientist. But there are materials scientists who would consider me to be a rather theoretical materials scientist. In the later years of my conversion I supported and promoted materials processing in the department although it took me rather a long time to get to this view, to appreciate the importance of this field, and to realise the need and potential for modelling.

BBV : What is your concept of materials science ?

PH : I am close to Merton Flemings's concept. To me materials science is an enabling science. We study material composition, structure, properties and processing for applications in engineering. There is now a strong group on processing here. Not only casting but various kinds of processing like spray forming, coating, making magnetic and superconductor devices etc. There are also two lecturers working on polymers now.

BBV : Does polymer synthesis now belong to Materials Science ?

PH : Polymer processing and modelling properties belong to materials science, but synthesis of new kinds of polymers - I doubt if this is a proper activity for a materials department, although it would be quite appropriate as a joint research activity with Chemistry. That would be my view for what it is worth. But composition, structure, properties, performance, Merton Fleming's picture, defines Materials Science.

BBV : What about the recent addition of end-users to this picture ?

PH : Yes end-users are important but I would consider that this links in with performance. The interaction with industry is important. Quite apart from the problem of funding it is vital for materials science, as an enabling science.

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« Entretien avec Peter Hirsch », par Bernadette Bensaude-Vincent, 12 décembre 2002 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article126.
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Entretien avec Peter Hirsch, par Bernadette Bensaude-Vincent, 12 décembre 2002

Lieu : Materials Department, Oxford University

Support : enregistrement non précisé

Transcription : Bernadette Bensaude-Vincent

Edition en ligne : Sophie Jourdin

HAGENMULLER Paul, 2001-06-12

Sophie Jourdin — 2011-11-03T15:23:16Z

Paul Hagenmuller, born in Alsace in 1921, developed solid-state chemistry in France. He first initiated a research program at the University of Rennes (1956-60). In 1960 he set up a dynamic laboratory in Bordeaux. In 1964, Hagenmuller organized an international conference dedicated to the relations between structure and physical properties in oxides of the transition elements. The meeting gathered together chemists, crystallographers and solid-state physicists and prompted the establishment of an international community of solid-state chemists. In Bordeaux, Hagenmuller became the head of a research school working, at the interface between physics and chemistry, on the relation between atomic/electronic structure and physical properties, with a strong emphasis on industrial applications.

The Bordeaux research school has attracted scientists and students from all over the world (both developed and emerging countries) and many brilliant chemists of the next generation such as Jean Rouxel were trained in Bordeaux. Paul Hagenmuller retired in 1994. A jubilee celebration was organized at the Maison de la chimie in Paris in 1997. In 2001, his 80th birthday was celebrated in a special issue of the journal Solid State Chemistry.

HERVE ARRIBART (HA) : Pouvez vous retracer votre formation, vos débuts dans la carrière ?

PAUL HAGENMULLER (PH) : Depuis que je m'intéresse à la science je me suis préoccupé de la physique. Je me suis demandé pourquoi les matériaux avaient telle ou telle couleur, tel ou tel comportement électrique, magnétique, optique ... J'ai donc été porté vers la physique, plus tard vers la mécanique par extension, dès que j'ai entrepris mes études de science. Ces études ont eu lieu en 1940 à l'université de Strasbourg, repliée à Clermont Ferrand. Mon statut était celui d'un réfugié politique puisque j'avais quitté l'Alsace pour échapper au système politique allemand et parce que je me refusais d'être un jour mobilisé dans l'armée allemande. A Clermont, pour des raisons financières j'ai fait le choix de la chimie, séduit par la diversité des méthodes de préparation mais choqué parce que la chimie était alors très descriptive et n'était pas encore une science déductive, de réflexion.
Sur place, je suis entré en résistance, je faisais du sabotage. J'ai été arrêté en 1943 et envoyé en camp de concentration à Buchenwald. Là j'ai appris à me taire. J'ai travaillé sur les V2. J'ai appris le russe avec les prisonniers russes ; j'avais de bons contacts avec les communistes allemands. Puis j'ai été envoyé à Dora où c'était plus dur.
Après la guerre, André Chrétien m'a proposé un sujet de thèse sur la formation de nitrites complexes en solution aqueuse, puis une recherche sur la réduction de divers oxydes par des hydrures d'alcalino-terreux. J'ai accepté parce qu'il y avait un appareil mathématique. Puis au lendemain de ma thèse je me suis dit : il faut que je travaille sur des choses plus concrètes, les matériaux. J'ai voulu revenir à mes anciennes amours les matériaux. Je suis parti au Vietnam dans le cadre d'un accord avec la direction de l'enseignement supérieur et moi. Je partais pour deux ans 1954-56, au moment où la France se désengageait et voulait garder des relations culturelles. Au retour il était entendu que je pourrai choisir un poste de maître de conférences parmi ceux qui étaient disponibles en chimie. Ces deux ans de Vietnam ont été pour moi une période de décantation, de réflexion. Et quand je suis revenu j'ai voulu, d'une part, me préoccuper de physique ce qui suppose la détermination des structures atomiques - pour comprendre les propriétés physiques il faut savoir quelles sont les positions des atomes - et, d'autre part, il faut une certaine habileté à préparer des matériaux par des techniques nouvelles fort différentes.

HA : Quelles étaient alors les relations entre physique des solides et chimie des matériaux en France ?

PH : Aujourd'hui la physique s'est beaucoup rapprochée de la chimie parce que, de part et d'autre, on a compris que c'était indispensable pour faire des matériaux à propriétés spécifiques intéressantes sur le plan de la science fondamentale et intéressantes aussi sur le plan des applications. Au début des années 60, on en était à se chercher. Moi, j'avais fait un choix très clair : faire une chimie orientée vers la physique, plus tard vers la mécanique. Maintenant c'est devenu presque de routine, ne serait-ce que par ce que les chimistes pour bien connaître leurs matériaux sont obligés d'utiliser des méthodes de caractérisation physiques. La physique s'est imposée dans les perspectives de la recherche comme par les nécessités quotidiennes : savoir où sont les atomes et les électrons.
Donc au retour du Vietnam mon objectif était d'associer la physique et la chimie. J'ai eu la chance que dans mon poste à Rennes il y avait quantité d'excellents étudiants, mais en chimie personne ne voulait faire de la recherche sous prétexte qu'il n'y avait pas de moyens. J'ai décidé que j'allais lancer des thèses dans ce domaine à l'interface de la physique et de la chimie. On a d'abord tâtonné. On a travaillé sur le bore, sur les hydrures. Parmi les études réalisées à Rennes se trouvait la réduction d'oxydes par l'hydrure de lithium. On était intéressé par les hydrures de bore et d'aluminium qui comportaient des liaisons dites pont-hydrogène originales. Ceci m'a donc amené à réduire le V2O5 par l'hydrure de lithium et nous avons constaté qu'il y avait des phases intermédiaires qui devaient être les futurs bronzes de vanadium et de lithium, qu'on a appelées plus tard b et g. La phase a étant la solution solide de lithium dans V2O5. Alors j'ai pensé que ces matériaux étaient intéressants : s'il y a là un domaine d'existence, les propriétés physiques doivent varier à l'intérieur de ce domaine et si, par chance, ce domaine est suffisamment grand on peut faire ce qui est plus difficile dans les solutions solides limitées, de type oxydes non stœchiométriques. On s'est préoccupé de manière systématique des bronzes de vanadium qu'on a préparés par voie synthétique. Dans les années qui ont suivi - de 1960 à 70, j'étais alors à Bordeaux où un grand nombre de chercheurs de Rennes m'avaient suivi - on a préparé un grand nombre de phases de bronzes de vanadium par analogie avec les bronzes de tungstène qui avaient déjà été signalés. On a fait systématiquement des études magnétiques et électriques pour caractériser le mode de conductivité. Il est apparu que lorsqu'on insérait le lithium dans le réseau, on remplissait les états électroniques du vanadium, qui forment la bande de conduction. Les électrons devenaient donc de plus en plus délocalisés au fur et à mesure que leur nombre augmentait et on passait d'un état semi-conducteur à l'état métallique.

BERNADETTE BENSAUDE-VINCENT (BBV) : Quelles étaient vos relations avec le groupe de Robert Collongues ?

PH : Collongues avait été élève de Georges Chaudron, comme André Michel, Paul Lacombe, Jacques Bénard. J'avais d'excellentes relations avec Collongues. Nos domaines se recouvraient partiellement sur la non-stœchiométrie mais on avait des approches différentes. Lui enlevait des ions, nous on faisait de la chimie d'insertion. Collongues aimait bien se singulariser par rapport à moi mais dans la pratique nous avions la même politique sur des matériaux différents. Il y avait chez lui le même désir de systématique et de réflexion en profondeur. Collongues considérait que la bonne expérience était importante mais qu'elle devait illustrer une réflexion de fond. Il pensait que la science était avant tout la réflexion intellectuelle.
J'ai fait de la chimie sous pression à la manière d'un tailleur : choisir une structure cristallographique, écrire la formule d'une composition chimique, puis la stabiliser dans un degré d'oxydation élevé. Après avoir discuté la structure puis la formule, on préparait sous haute pression. C'était du design pour la conductivité électronique, les propriétés magnétiques, ou les propriétés magnéto-optiques et plus tard également pour la conductivité ionique.
Nous nous intéressions systématiquement à l'évolution de toute propriété physique originale en fonction de la composition et de la structure. Un nœud important dans cette évolution fut le colloque organisé à Bordeaux en 1964 sur les oxydes d'éléments de transition.

HA : Quelle fut la portée de ce colloque de 1964 ?

PH : Ce fut le moment où s'est constituée une communauté internationale de chimie du solide. Le colloque a rassemblé les chimistes qui nous étaient familiers, des cristallographes (Erwin-Felix Bertaut, Charles Guillaud), des physiciens (Jacques Friedel). Parmi les étrangers Mike Sienko, John Goodenough du Lincoln Laboratory au MIT qui est venu pour la première fois à Bordeaux ; des Allemands : Wilhelm Klemm, Rudolf Hoppe, Harold Schäfer ; des Hollandais, des Belges, etc. Il est apparu qu'une conjugaison des méthodes de mesure physique, des méthodes de détermination structurale et une certaine flexibilité pour les changements de composition, pouvaient permettre d'optimiser un certain nombre de propriétés physiques. D'abord le magnétisme, ensuite il y a eu la ferro-électricité - comment accroître la distortion ferro-électrique et par voie de conséquence la polarisation ; enfin, la conductivité ionique, d'abord dans des matériaux isolants au point de vue électronique et ensuite dans des matériaux dits cathodiques utilisables dans des batteries parce que conducteurs mixtes.
Je dois dire que ce qui fut déterminant pour l'avenir de la chimie du solide ce fut la venue de John Goodenough à ce congrès parce qu'il a popularisé parmi nous l'idée de l'importance de la liaison chimique. On a compris qu'on pouvait renforcer ou atténuer la liaison chimique en modifiant la composition, en particulier en jouant sur la liaison antagoniste. Par exemple si on compare le zirconate de baryum avec le titanate de baryum, la liaison baryum-oxygène est renforcée dans le zirconate par rapport au titanate. Inversement si on remplace dans le titanate de baryum, le baryum par le strontium comme la liaison strontium -oxygène est plus forte que la liaison baryum-oxygène, la liaison titane-oxygène est affaiblie, ce qui peut amener une variation très forte de la polarisation en fonction de la température, juste en dessous de la température de Curie. Et on peut avoir ainsi des matériaux aux propriétés intéressantes.

HA : Le rapprochement de la physique et de la chimie avec une orientation vers les applications constituerait-il donc l'identité de la chimie du solide à cette époque ?

PH : Oui nous avions un besoin civique de justifier les crédits que nous demandions par une application dans la vie économique. De plus, le travail avec des industriels fait naître des problèmes inattendus qui sont des challenges et qui sont nourrissants.
Une deuxième date importante dans l'institutionnalisation de la chimie du solide est 1978. Sur mon initiative la Société française de Chimie a créé en 1976 une division de chimie du solide, dont j'ai naturellement été le président. J'ai organisé la même année un premier colloque national de chimie du solide à Nantes. Sur ma proposition et sous ma présidence s'est tenu à Strasbourg en 1978 le premier congrès européen de chimie du solide, organisé par Jean-Claude Bernier (Strasbourg a été choisi pour une raison stratégique,). L'intervalle entre deux congrès consécutifs est maintenant de 3 ans ; le huitième congrès européen a lieu en juillet 2001 à Oslo.

HA : Quel était l'état des relations entre science et industrie en France à cette époque ?

PH : Il y avait une tradition de collaboration en métallurgie et en chimie : Chaudron et ses élèves, Lacombe, Bénard étaient très impliqués. Robert Collongues l'était aussi dans le domaine des monocristaux. Mais il y avait une forte hostilité syndicale au nom des grands principes : il ne faut pas mettre la science au service des grands intérêts privés. Les choses se sont atténuées à la veille de l'élection présidentielle de 1981. J'ai eu la visite de M. Kahane, longtemps doyen à Orsay, qui s'était rallié à la collaboration avec l'industrie privée. Cela a facilité cette évolution qui, de ma part, ne rencontrait aucune résistance car j'étais un scientifique et je n'avais pas à me poser des problèmes de déontologie qui me paraissaient un peu artificiels. Mais une partie de mon entourage était réticente à travailler avec l'industrie.

HA : Est-ce la crise pétrolière de 1973 qui a contribué à anoblir le rapprochement entre science et industrie ?

PH : Oui. Du fait de notre préoccupation entre propriétés physique et composition, nous avons été conduits à travailler sur des composés non-stœchiométriques d'intercalation et nous avons constaté après 1973 qu'il y avait possibilité d'intercalation ou désintercalation à basse température grâce à l'électrochimie comme on le faisait aux Etats Unis. Exxon et Bell étaient plus concernés que nous par la crise de l'énergie.
Les recherches sur la conductivité ionique ont été encouragées par la crise de l'énergie. Après la zircone déjà exploitée par Nernst, puis étudiée par la NASA et par Collongues ; il y avait eu AgI. Puis il y a eu l'alumine-b qui a suscité de nombreux travaux. CGE a dépensé beaucoup d'argent. L'alumine-b est un matériau très particulier. J'étais très sceptique. On a abaissé la température de fonctionnement, mais c'est encore trop haut pour un véhicule électrique. Et puis le soufre attaque la membrane. Finalement on a renoncé, pensant qu'avec des batteries au lithium on irait plus loin. Les derniers efforts de développement visaient plutôt le stockage d'énergie en période creuse. Les nasicons eux ne sont pas attaqués et ils présentent un avantage au plan fondamental car leur structure est plus simple. Ils ont de bonnes performances, qu'on pouvait maîtriser avec une juste proportion de sodium.

HA : Pouvez vous évoquer vos travaux sur la conduction ionique ?

PH : Avant 1973, on a publié un grand nombre de documents sur des conducteurs ioniques. On s'inspirait comme modèle de réflexion des bronzes de tungstène bien que la plupart des travaux publiés à l'époque fussent des études structurales et que les bronzes de tungstène soient métalliques. On avait également préparé une série de nouveaux bronzes de tungstène. Ce travail s'est étendu à des bronzes oxyfluorés, à des bronzes de vanadium et de molybdène contenant les deux cations vanadium et molybdène plus le sodium et le lithium. Puis au début des années 1970, on s'est attaqué aux premiers bronzes de manganèse NaxMnO2 et puis aux bronzes de cobalt KxCoO2.
Sur ces entrefaites il y a eu la grande crise pétrolière de 1973. Les pays occidentaux ont eu peur de manquer d'énergie et donc on s'est occupé de sources d'énergie non fossile et de stockage d'énergie. Un certain nombre de gens ont voulu faire des batteries. Exxon et la Bell Telephon, Whittingham et Murphy en particulier, ont travaillé sur ces matériaux non plus comme nous l'avions fait vers 500°C avec des phases en équilibre thermodynamique mais à basse température par intercalation ou désintercalation électrochimique.
Une spécialité à Bordeaux c'était les fluorures conducteurs. On remplaçait systématiquement l'oxygène par du fluor parce qu'il a la même taille et présente une liaison plus faible. On pouvait ainsi atténuer les interactions magnétiques. Comme pour la zircone, on dope les fluorures systématiquement. Watanabe avait déjà préparé les premières batteries au fluor.
Jean Rouxel s'était intéressé à l'époque où il était mon élève aux sulfures, aux sulfures à couche en particulier. Entre les couches de FeOCl et FeSCl par exemple, on pouvait intercaler beaucoup de choses, comme l'ammoniac ou les amines. Jean Rouxel a préparé NaxTiS2, un matériau qui avait été préparé par Rudorf à Fribourg, qui le considérait comme une curiosité. Mais Rouxel a très vite réalisé qu'il devait y avoir un domaine d'existence. Or il s'est avéré que Li xTiS2 avait un large domaine d'existence. Jean Rouxel a poussé dans cette voie et il a étudié un grand nombre de sulfures et sélénures à feuillets alors que nous nous intéressions plutôt aux oxydes. Il y avait une sorte d'accord empirique entre nous : Nantes les sulfures, Bordeaux, les oxydes. Nous avons étudié des matériaux sur le plan de la synthèse, dans des conditions d'équilibre thermodynamique plus que par intercalation désintercalation.
Il y a une grande variété de méthodes topologiques ou non de relative basse-température qui permettent d'obtenir des matériaux nouveaux. Mettre un mélange très fin de poudres sous hautes pression pour que se déclenche une réaction brutale qui prend fin lorsque l'un des deux constituants initiaux a disparu. Donc c'est un échauffement brutal suivi d'une trempe. Ce qui permet d'obtenir des borures ou des silicium stables seulement à haute température.
Beaucoup de ces matériaux sont métastables mais on peut les utiliser dans des dispositifs.
Jean Rouxel a apporté beaucoup dans le domaine des réactions d'intercalation-désintercalation. Les oxydes lorsqu'on les désintercale perdent des électrons cationiques. C'est une oxydation cationique. Lorsqu'on part de LixCoO2 vers CoO2 on perd des Li+, mais on perd également des électrons qui proviennent des niveaux d. Mais pour les séléniures, ce sont les niveaux anioniques qui sont les plus élevés. Et lorsqu'on oxyde, c'est l'anion qu'on oxyde. On passe de Se2- à Se- et de Se- à Se pour des raisons de stabilité de liaison. Et Jean Rouxel a montré qu'il y avait une évolution graduelle pour les éléments 3d à l'état de sulfure entre TiS2, qui a une structure à couches, et CuS2 qui a une structure avec un ion S de type pyrite. Il a fait une analyse précise dans les cas douteux où les niveaux cationiques et anioniques sont à peu près de même énergie. L'analyse très fine des distances inter-atomiques lui a montré si c'était le cation ou l'anion qui était oxydé. Il a également fait beaucoup de choses sur les bidimensionnels qui sont ici hors sujet.

HA : Qu'est-ce qui a manqué en France alors que les compétences étaient là pour donner l'impulsion sur les batteries au Lithium ?

PH : Il y a un très grand nombre de batteries réversibles au lithium pour des applications diverses depuis les montres jusqu'aux batteries de taille moyenne utilisées par les militaires pour observation spatiale avant bombardement. Mais le marché important, c'est le véhicule électrique, non polluant. Du moins en partie car on s'est résigné au véhicule hybride. Le véritable marché ce serait la voiture électrique -éventuellement hybride- ce qui suppose des batteries de grande taille. Probablement l'électrolyte sera un polymère PEO imprégné d'un sel de lithium avec un gros anion, type matériau Armand. La cathode sera probablement riche en cobalt ce sera un matériau voisin de LixCoO2, plutôt un oxyde qu'un sulfure parce que la tension est plus élevée. Mais pour l'anode ce n'est pas encore évident. Si on pouvait faire mieux que les composés d'intercalation du lithium on serait content. Mais actuellement il n'y a pas encore de solution. Il y a donc premièrement un problème de matériau qui freine cette évolution. Deuxièmement il y a un problème de prix. Ajoutez à cela qu'une batterie au lithium doit être scellée car le lithium est sensible à l'atmosphère et vous voyez que ce n'est pas évident. Une solution concurrente est la batterie hydrogène consistant à stocker l'hydrogène dans un alliage métallique et puis à libérer l'hydrogène. Ce modèle permet des puissances plus élevées que la batterie au lithium mais là aussi il y a un problème de vieillissement car après un certain nombre de cycles, l'alliage s'oxyde car l'oxyde est plus stable que l'hydrure. Ce problème n'est pas encore résolu avec un coût acceptable pour l'utilisateur. A cet égard, il y a une coupure entre le scientifique et l'utilisateur.

HA : Concernant les relations entre physique et chimie qu'est-ce qui a favorisé le rapprochement ?

PH : Les physiciens ont fait des efforts pour parler un langage plus proche de celui des chimistes. J'ai parlé déjà de John Goodenough. Nevil Mott aussi était un homme qui s'exprimait dans un langage compréhensible pour un chimiste. Par exemple, lorsqu'il a obtenu des transitions isolantes par changement de composition au sein d'un domaine d'existence, on comprenait ses préoccupations et il comprenait les nôtres bien qu'on raisonne sur des modèles un peu différents. On est ainsi arrivé à préparer dans des bronzes de tungstène oxyfluorés des matériaux qui sans changement de structure manifestaient une transition métal-isolant. Les physiciens ont fait des progrès. L'équipe de Friedel était très préoccupée de parler un langage qui nous était commun. Je pense à Denis Jérôme, Claude Berthier à Grenoble.

HA : Le travail de physiciens sur la caractérisation très fine vous a-t-il aidé ?

PH : Je me souviens de discussions à Orsay sur les hexaborures. Les physiciens voulaient des matériaux qu'on appelait thermo-ioniques - mais c'est un mot malheureux : on devrait plutôt dire thermo-électronique - c'est à dire ayant un faible potentiel d'ionisation et susceptibles de cracher un jet d'électrons relativement puissant sous tension faible. On en a fait une étude systématique et on a essayé de préparer des cristaux.

HA : Et quel était l'enjeu ?

PH : L'enjeu était d'avoir ponctuellement un faisceau d'électrons puissant, par exemple pour des soudures, des soudures localisées. Outre la collaboration avec les physiciens d'Orsay on a aussi collaboré avec ceux de Grenoble. Plus que ceux d'Orsay, les physiciens de Grenoble avaient un langage très compréhensible. Il y avait un grand homme à Grenoble, Louis Néel. Il avait publié son travail sur le ferrimagnétisme en s'appuyant sur des modèles structuraux très clairs. La répartition des cations entre les sites tétraédriques et les sites octaédriques de la structure spinelle. Donc on comprenait pourquoi on avait des interactions d'abord anti-ferromagnétiques - ce qui constitue la base du ferrimagnétisme - entre des sites tétraédriques A et des sites octaédriques B, et pourquoi l'aimantation résultante était accrue lorsque le réseau prévalent contenait des cations avec beaucoup d'électrons d célibataires. Tous ces travaux - encouragés par les recherches militaires - ont permis une collaboration très fructueuse avec Grenoble. Je pense à Bertaut en particulier. Nous avons été encouragés, par exemple, à faire des études basse-température par Pauthenay qui nous a dit : c'est aux basses- températures qu'on détecte les phénomènes peu énergétiques.
Alors c'est l'époque où nous avons manqué le prix Nobel - Je dis cela en plaisantant, bien sûr !-. Nous avons préparé les premiers oxydes purs de Cu3+ : par exemple SrLaCuO4. Nous avions une telle habitude des solutions solides qu'on pouvait imaginer de préparer une solution solide avec La2CuO4 contenant du Cu2+. Mais pour nous, les solutions solides, c'était du travail secondaire. On cherchait à préparer des oxydes purs. Si on avait été préoccupé des solutions solides on aurait pu trouver des oxydes contenant à la fois du cuivre Cu 2+ et 3++. Comme par routine on caractérisait tous nos matériaux jusqu'à la température de l'hélium liquide, on aurait trouvé la supraconductivité. On ne l'a pas fait parce qu'on voulait des phases pures et non pas des solutions solides.
Bernard Raveau l'a fait avant Alex Müller. Il avait un objectif : comprendre ce qui se passait au point de vue des corrélations. Passer d'un semi-conducteur à un métal. Müller était un très grand physicien. Il a été surpris aussi mais il a tout de suite expliqué. Raveau a fait ses solutions solides. C'est même moi qui ai transmis sa publication au M[aterials] R[esearch] B[ulletin] mais j'ai regretté à l'époque qu'il n'ait pas fait de mesure à l'hélium liquide.

HA : Après avoir évoqué vos collaborations en France, pourriez vous parler de vos liens avec l'étranger ? Vous avez été précurseur pour les relations scientifiques avec les pays en voie de développement comme la Chine, le Maroc et l'Inde. Quelles étaient vos motivations ? Comment voyez-vous la science des matériaux dans ces pays ?

PH : J'ai toujours été persuadé que la science devait être internationale. Cela me distingue de beaucoup de mes compatriotes. Je suis toujours étonné que l'on fasse des quêtes pour aider la recherche en France sur le SIDA. Toute la recherche sur le SIDA, toute recherche de pointe est internationale et ce n'est pas parce que la France dépensera un peu plus d'argent que nécessairement, il y aura des progrès significatifs. La science doit être internationale.
J'ai donc eu des liens d'abord avec les pays développés car dans ce type de relation on se fait connaître mais aussi on apprend. Je suis allé souvent aux Etats Unis, moins par enthousiasme culturel, que parce qu'on y rencontre des gens de qualité. J'ai rencontré Goodenough, Al Cotton... j'ai rencontré à Berkeley ou à Stanford des gens de grande qualité. J'ai eu des relations suivies pendant un temps avec la Grande Bretagne mais les Anglais ont un sentiment de quant à soi. J'espère qu'avec le temps la Grande Bretagne va évoluer vers une intégration dans l'Europe. Les Allemands sont très favorables à cette intégration. Dès 1961 j'avais pris l'initiative d'emmener tout mon laboratoire en Allemagne pour un voyage de 15 jours. On est allé à Stuttgart, Karlsruhe, Heidelberg, Darmstadt, Giessen, Göttingen etc.. On a été très bien reçu par Wilhelm Klemm avec qui j'ai toujours entretenu d'excellentes relations. Mais ses élèves étaient jaloux. Les Allemands se sont sentis bousculés parce qu'un peu jaloux de gens qui faisaient beaucoup de bruit. Ils avaient une bonne tradition de chimie préparative, en relation avec l'industrie. Les Allemands ont compris que pour faire des matériaux nouveaux il fallait des techniques nouvelles comme la haute pression. Mais leur but c'était la performance tandis que le nôtre c'était de stabiliser des structures électroniques peu usuelles, grâce à la synthèse. Les Allemands se sont senti un peu gênés. Les gens leur disaient : vous utilisez des équipements de haute pression mais ce que vous faites c'est de la botanique alors qu'il faudrait réfléchir. Le but d'un équipement est de faire des matériaux à façon pour répondre à des problèmes déterminés. Les collègues allemands avaient un autre point de vue et je regrette qu'il n'y ait pas eu davantage de liens.
En revanche, toujours parmi les pays développés, j'ai eu beaucoup de liens avec l'Europe de l'Est. Pour deux raisons. D'abord, il y avait des gens de qualité chez les Soviétiques, les Polonais et les Tchèques. De plus j'étais un peu agacé de cette Europe coupée en deux du fait de la guerre froide. Donc je trouvais raisonnable qu'il y ait une présence de la France là où c'était relativement facile, c'est à dire la science. C'était intéressant pour eux et pour nous car nous avons eu de ces pays des personnes remarquables. J'ai eu des relations systématiques avec des laboratoires à Prague, Cracovie, à Moscou, à Kiev, Novosibirsk, à Sofia. Avec la Roumanie, c'était impossible car Madame Ceaucescu interdisait aux scientifiques de discuter avec des étrangers.
Avec les pays en voie de développement, la situation change d'un pays à l'autre. J'ai eu des relations avec le Maroc parce que l'université de Bordeaux et l'université de Rabat avaient des liens traditionnels. Je suis allé y faire cours. Il y avait de très bons étudiants je les ai encouragés à faire une thèse. Le nombre a crû considérablement. 30 ou 35 Marocains ont fait des thèses avec moi. J'avais une politique de sélection impitoyable ; je prenais les meilleurs et je les surpayais. Je voulais qu'ils n'aient pas de souci matériel pendant leur thèse. J'ai eu des liens plus occasionnels avec la République du Congo et quelques Tunisiens mais ils préféraient Marseille.
Avec la Chine j'ai fait un choix politique. J'ai compris que la Chine était un potentiel économique et humain. La France devait être présente à un moment où la Chine était exclusivement tournée vers les Etats-Unis. Je suis allé souvent en Chine. J'ai fait venir des étudiants chinois en les choisissant bien sûr excellents. Mes espoirs ont été dépassés par le succès car ils ne sont pas retournés en Chine mais partis au Canada ou aux Etats-Unis comme professeurs ou dans l'industrie. Ils se sont bien débrouillés. Maintenant c'est différent ; une majorité d'étudiants chinois reviennent en Chine.
L'Inde est aussi un pays avec lequel j'ai eu des relations. C'est une société où le savoir est respecté, une science de caste malgré l'abolition officielle des castes. Thaïlande, Malaisie, Indonésie...j'ai privilégié les pays asiatiques par rapport aux pays africains car la culture asiatique favorise la réflexion métaphysique et par conséquent scientifique. Néanmoins j'ai eu aussi des collaborations avec le Brésil, le Chili et l'Argentine. Le but étant d'aider ces pays dans leur développement industriel. Je suis d'ailleurs membre de l'Académie des sciences brésilienne depuis 1988.
Vis à vis des étudiants du tiers monde, j'ai toujours considéré comme ma responsabilité de leur donner une thèse originale et non pas, comme on le fait souvent, de leur faire remplir des vides dans le laboratoire ou de servir de main d'œuvre. Les étudiants du tiers monde que l'on fait venir en Europe il faut bien les choisir et bien les former pour qu'ils deviennent des maîtres.

HA : Je serai curieux de connaître votre point de vue sur l'évolution de la chimie des matériaux et le rapprochement avec la biologie.

PH : Je ne me sens pas compétent dans l'interface chimie/biologie. Mais mon expérience à l'interface physique et chimie me rend plutôt sympathique cette perspective d'une ouverture de la chimie vers la biologie. Elle est défendue par Pierre Pottier, Guy Ourisson, Corriu.
Sur l'interface physique/chimie, cela s'est moins bien passé. Peut-être que je n'ai pas su convaincre. Quand on prêche, on se fait des adeptes mais aussi des ennemis. Cela est vrai au CNRS. Celui qui prêche secoue les caciques, les gens en place. Quelqu'un comme Fernand Gallais était fermement hostile à mon projet d'interface avec la physique. Par contre j'ai rencontré beaucoup de sympathies du côté de Pottier, de Jacques Livage.
Pour revenir aux oxydes supraconducteurs, il s'agit d'un cas intéressant de collaboration entre physiciens et chimistes. Très vite, j'ai compris que l'on avait plafonné et puis à un moment donné il était clair que Tc était d'autant plus élevé que la bande de conduction était plus étroite. Et plus la bande de conduction est étroite plus le matériau est instable et a tendance à se dismuter en donnant un mélange de deux phases. J'ai compris cela très vite mais beaucoup ne l'ont pas compris. Il y a donc eu un emballement. Il a rapproché les chimistes des physiciens. Il est dommage que personne n'ait proposé un modèle simple permettant aux chimistes d'innover de manière simple comme on avait innové dans le domaine de la conductivité ionique, du magnétisme, de la ferroélectricité, des magnéto-optiques ... ou même des composites thermo-structuraux. Il a manqué quelqu'un qui propose un modèle intuitif liant les propriétés à la liaison chimique. Goodenough aurait pu le faire mais il était trop vieux, trop pressé de publier des matériaux miracles. Les matériaux miracles sont difficiles à reproduire. Celui qui essaie il n'a pas le même four ... Ces matériaux sont métastables, ils ne sont jamais parfaitement purs. Ils n'ont jamais le même nombre de lacunes d'oxygène. Donc ce n'est jamais parfaitement répétitif. Cela exclut toute réplication sérieuse parce qu'un matériau n'est utilisable industriellement que s'il est relativement simple à préparer et à utiliser. Telle est la raison de l'échec de la diode Josephson sur laquelle IBM a dépensé beaucoup d'argent. A l'époque j'étais d'ailleurs conseiller d'IBM.

BBV : Est-ce qu'il y a eu des matériaux sortis de vote laboratoire qui ont été industrialisés ?

PH : Il y a d'abord eu les varistors. J'ai fait beaucoup avec la Thomson CSF dans ce domaine. Il y a eu LixCoO2 et puis il y a les céramiques composites de R. Naslain : fibres de carbone infiltrées par SiC qui permet de travailler à des hautes températures pour les matériaux de rentrée de la fusée ou du satellite dans l'atmosphère. Car lorsque l'engin revient dans l'atmosphère, il y a un risque d'oxydation. L'astuce consistait à infiltrer - non pas déposer en surface - SiC à partir d'une phase vapeur. Alors à l'air SiC s'oxyde en donnant SiO2 qui s'infiltre dans le matériau à base de carbone et permet de le prolonger.

BBV : Pourriez vous préciser quelles étaient vos relations avec l'industrie et comment elles ont évolué ?

PH : J'ai toujours eu des relations avec l'industrie. Quand j'étais à Rennes j'ai été contacté par Raymond Paul, un des responsables de la recherche à Rhône Poulenc et il m'a vivement encouragé à travailler avec Rhône Poulenc. J'ai eu plusieurs bourses de thèses payées par l'industrie - parfois il fallait publier des résultats plus tard. Rhône Poulenc a payé la thèse de Michel Pouchard sur les bronzes de vanadium au début des années 60. Ensuite il m'a paru tout naturel de travailler avec l'industrie. J'ai travaillé avec Saint-Gobain sur les verres, en particulier sur les verres conducteurs du lithium et du sodium avec Levasseur, sur les verres sulfurés à base de B2S3. Les verres sont un matériau merveilleux. Ils ont une composition qui est flexible. Vous tombez un peu à côté, cela n'a pas d'importance les propriétés ne sont guère modifiées. Vous n'avez pas le problème des matériaux cristallins où, par suite de la moindre erreur, de la moindre difficulté de préparation, une deuxième phase d'impuretés se forme à côté. Là il vous reste une phase. D'autant plus qu'on peut préparer les verres par trempe brutale donc énormément de matériaux sont vitreux alors qu'il y a 30 ou 40 ans c'était différent.
J'ai eu beaucoup de liens avec l'industrie locale : Aérospatiale et SNECMA, avec SNPA (société nationale des pétroles d'aquitaine : ancêtre d'Elf) sur comment purifier le gaz de Lacq...Ma porte était toujours ouverte, on élargissait le champ de nos recherches à la demande car l'industrie n'est pas un boulet.

BBV : Est-ce que ces liens étaient encouragés par le CNRS ?

PH : Le CNRS était informé bien sûr. Et puis quand on est devenu un laboratoire propre en 1966 Curien était très favorable aux relations avec l'industrie. On a un des contrats avec Saint-Gobain, avec Rhône Poulenc devenu Rhodia, avec Ugine Kuhlman devenu Péchiney. Nous avons même eu des liens avec General Electric aux USA pour les borures, avec BASF sur le di-oxyde de chrome pour les bandes d'enregistrement.

BBV : Quelles sont les méthodes et techniques utilisées dans votre laboratoire ? Et comment ont-elles évolué au cours de votre carrière ?

PH : Au début le B-A-BA c'était la diffraction X. Puis pour bien comprendre la structure on a eu un équipement pour des monocristaux. On a préparé des mono-cristaux pour déterminer les structures. Maintenant on a fait de gros progrès et on peut sur des spectres de poudres lorsque la poudre est de bonne qualité déterminer la structure par les méthodes Riedveld en faisant des hypothèses simples sur la structure la plus probable. La diffraction X a été fondamentale et a débouché ensuite sur la microscopie électronique en transmission qui permet de voir les défauts locaux. C'est merveilleux. La diffraction X était une méthode à grande distance. Par contre la microscopie électronique en transmission vous donne les défauts localisés et étendus. C'est une préoccupation que j'ai eu beaucoup à propos de non-stœchiométrie. Quand on passe d'une phase perovskite ABO3 à une phase brownmillérite A2B2O5, on perd de l'oxygène. Alors à haute température les lacunes d'oxygène sont désordonnées. A température plus basse, elles s'ordonnent en fonction du cation B. Quand c'est du fer ou du gallium, un cation isotrope, on a soit des tétraèdres parce qu'il y a pas de lacune, soit des octaèdres car les lacunes marchent par deux. Donc dans une structure brownmillérite on a une séquence octaèdre,-tétraèdre, octaèdre-tétraèdre, et dans la structure perovskite c'est octaèdre-octaèdre-octaèdre. Alors on peut trouver à condition de faire des recuits à température assez basse - quelques centaines de degrés - des phases intermédiaires avec 2 couches octaèdres, 1 couche tétraèdre, 3 couches octaèdres, 1 couche tétraèdre. Et bien sûr quand on chauffe le désordre s'installe à cause de l'entropie d'empilement. On a étudié de manière systématique comment on passe de défauts isolés aux défauts ordonnés, étendus. Et cela a des conséquences au point de vue de la conductivité de l'ion oxygène. Parce que maintenant on a de nouvelles préoccupations. On veut par exemple extraire l'oxygène de l'air par des membranes de perovskite lacunaire ou détruire les traces de CO en oxydant par l'eau. Dans ce cas, vous avez CO2 - qui est quand même moins toxique que CO, sauf sur le plan idéologique - et vous avez de l'hydrogène. On utilise des perovskites lacunaires qui doivent être conducteurs de l'oxygène - ce qui est normal - mais aussi conducteurs électroniques car le transfert se fait sous tension donc il faut que les ions O2- migrent à travers les lacunes de la structure. Il y a donc un aspect pratique pour les capteurs d'oxygène, la purification des gaz. Les Norvégiens utilisent ces méthodes massivement pour transformer le gaz de la Mer du Nord en un gaz exempt de CO. Norsk-Hydro dépense des sommes considérables pour cela. J'ai été invité pour parler avec les gens impliqués par ces recherches.
Donc pour résumer : nos efforts se sont situés à l'interface entre physique et chimie et se concentraient sur l'étude des relations entre composition, structure et propriétés avec la perspective d'applications industrielles.

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Pour citer l'entretien :

« Entretien avec Paul Hagenmuller », par Bernadette Bensaude-Vincent et Hervé Arribart, 12 juin 2001 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article124.
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Entretien avec Paul Hagenmuller, par Bernadette Bensaude-Vincent et Hervé Arribart, 12 juin 2001

Lieu : Paris, France

Support : enregistrement sur cassette

Transcription : Bernadette Bensaude-Vincent et Hervé Arribart

Edition en ligne : Sophie Jourdin

FRIEDEL Jacques, 2001-10-17

Sophie Jourdin — 2011-09-19T08:25:40Z

Jacques Friedel, born in Paris, February 11, 1921, entered the Ecole polytechnique (1944-46) then the Ecole nationale supérieure des mines (1946-48). He thus followed up the family tradition starting with his great-grand father Charles Friedel, a famous organic chemist and crystallographer at Paris Sorbonne, his grand-father Georges Friedel best known for his work on liquid crystals, his father Edmond Friedel who was the director of the National School of Mines (1937-65). Jacques Friedel obtained a Licence ès sciences degree at the University of Paris in 1948, then was initiated to physical metallurgy in the Metallurgy Laboratory of the School of Mines headed by C. Crussard. He spent three years at Bristol University (UK) in Nevill F. Mott's physics department. There he became acquainted with the electronic structure of metals and with dislocations, a topic developed by Charles Frank. In 1952 he got a PhD. from Bristol and a Doctorat d'Etat in Paris in 1954 on the electronic structure of impurities in metals.
In 1956, he became assistant professor at Paris University, then full professor of Solid State Physics at Paris Sud in Orsay from 1959 to 1989. For thirty years he developed a research school in solid state physics, authored a volume Les dislocations (Paris, Gauthier Villars, 1956, 2nd ed. Dislocations, Pergamon, 1964) and more than 200 journal articles. His original contributions dealt with various branches of solid state physics, in particular the electronic structure of metallic alloys and of metals, the structure of surfaces of dislocations and of clusters.

Jacques Friedel chaired the Consultative Committee to the French Government for scientific and technological research (1978-1980), was the President of the Société française de physique and of the European Physical Society. Among many responsabilities in French scientific institutions, Jacques Friedel became the President of the French Academy of Sciences (1992-1994)

Pour citer l'entretien :

« Entretien avec Jacques Friedel », par Hervé Arribart et Bernadette Bensaude-Vincent, 17 octobre 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article80.

JACQUES FRIEDEL (JF) : Je voudrais commencer par quelques remarques générales que m'inspire votre projet.
La première concerne la notion de matériaux. Le terme et ce qu'il représente pour l'enseignement comme pour la recherche font partie d'une évolution générale des universités après la Deuxième Guerre mondiale. Il faut se rappeler, en effet, que jusqu'à cette époque et au delà, les départements universitaires étaient définis par grands secteurs - mathématiques, physique, chimie, biologie, géologie, astronomie - à l'intérieur desquels les « chaires » professorales de spécialité étaient définies, en physique du moins, par la nature de l'instrumentation employée : cristallographie (c'est-à-dire rayons X), acoustique, optique, thermodynamique, etc. En chimie, par contre, l'opposition entre minérale et organique était transcendée par le développement plus récent de la chimie physique qui, avant guerre, avait tendance à couvrir le futur domaine des matériaux. Ces subdivisions existaient aussi dans les organismes de recherche comme le CNRS. Le développement des applications pratiques de la physique nucléaire comme des grands laboratoires de recherche industriels (Philips, GECO, Bell, IBM) avaient fait éclater ces divisions et montré la nécessité de repenser l'organisation de la recherche comme de l'enseignement.

C'est dans ce contexte lors d'une réunion de l'American Physical Society que Roman Smoluchowski a le premier, je crois, proposé le développement d'instituts de recherche et la création d'une société (américaine) centrée sur l'étude des matériaux. Elle devait regrouper chimistes, physiciens, mécaniciens et aussi cristallographes et métallurgistes alors dispersés dans diverses sociétés.
Cette proposition avait une résonance évidente dans les grands laboratoires appliqués, relevant soit de l'industrie soit d'organismes d'Etat. Mais elle était trop extrême pour la recherche universitaire. Celle-ci avait commencé à se réorganiser à l'intérieur de la physique comme de la chimie, en départements distincts mais spécialisés autour des particules et des noyaux, des atomes et des molécules, et finalement des solides. Pour ces derniers Bristol, avec N.F. Mott et bien d'autres, a été un premier noyau conscient et organisé, dès avant la guerre. Mais la personnalité de F. Seitz, auteur du premier livre sur la physique de l'état solide, a joué un grand rôle, avec la création au début des années 50 de son département de physique à Urbana (Illinois). De la même époque, datent l'Institut de physique des solides de Tokyo et le groupe de physique des solides de Pierre Aigrain à l'Ecole normale supérieure (Paris). Notre laboratoire de physique des solides a été fondé à Orsay en 1959. Le Max Planck de Stuttgart (Physique et chimie des solides) et le laboratoire correspondant du centre nucléaire de Jülich (Allemagne) datent des années 1960. Enfin, en France, le développement des 3° cycles universitaires à partir de 1955 s'est fait en physique et (sauf pour la cristallographie) suivant le même découpage. Peu après, le CNRS suivait la même voie pour réorganiser ses commissions avec une section « physique des solides » remplaçant, à ma suggestion, l'électronique, la thermodynamique et l'optique des solides. Toutes ces réformes confortaient le découpage des universités comme des organismes type CNRS ou Max Planck en domaines disciplinaires de physique, chimie, mécanique etc. Ce grand découpage sera maintenu dans la réforme Fouchet de l'université française en 1968. Elle supprimait en physique quelques vieilles chaires remplacées par des enseignements plus modernes, vus d'un point de vue plus général. Cette évolution s'est poursuivie dans les années 70 avec le passage vers 1975 de physique des solides à physique de la matière condensée. En Europe, ceci a permis de regrouper dans une même division de European Physical Society les gens des solides et les gens des liquides - sans oublier les cristaux liquides et les polymères remis à l'honneur par Pierre-Gilles de Gennes et d'autres. En France, le changement de dénomination a permis aussi aux cristallographes de rentrer dans le rang au CNRS, par la création de deux sections de matière condensée, au prix d'une séparation regrettable entre aspects atomiques et aspects électroniques.
C'est donc dans ce contexte général qu'il faut juger le développement du concept de matériaux. Aux USA, la création au milieu des années 60 d'instituts universitaires des matériaux - dont seuls certains ont survécu - a été présentée et jugée comme une tentative d'introduire l'interdisciplinarité dans un milieu encore dominé par le découpage en départements de grandes disciplines et par l'individualisme des enseignants, souvent encore instables et toujours dépendants de contrats personnels de recherche.
En France, les matériaux ont émergé officiellement en 1970-71. J'étais alors le premier président physicien (et non chimiste) d'une Action Concertée en Métallurgie de la DGRST (Délégation générale à la recherche scientifique et technologique, précurseur du ministère de la recherche). Cette action, comme bien d'autres en électronique, par exemple, avait pour but de favoriser l'octroi de contrats de 3 ans, des travaux en commun de laboratoires différents, appartenant si possible à l'université et à l'industrie. Sous la poussée du vent de réformes post-1968, la commission de cette Action concertée a bâti un programme d'enseignement des matériaux, animé par mon cousin et premier patron Crussard, alors de retour d'un voyage aux Etats Unis et membre de la Commission. Ce programme, qui accordait une place prépondérante aux matériaux de structure, a été immédiatement adopté par les écoles d'ingénieurs impliquées dans ce domaine (métallurgie, plastiques, céramiques). Il y a eu aussi la création de DEA universitaires en matériaux en province comme à Paris. Le rapprochement entre physiciens et chimistes, comme les débouchés industriels ont été jugés positifs. Les cristallographes y ont souvent vu une manière de s'épanouir, de former des gens qui iraient plus facilement dans l'industrie. En se séparant en 1971, cette Action Concertée de Métallurgie a laissé un rapport émettant le vœu qu'une Action Concertée Matériaux pour la recherche lui succède, en suggérant un premier programme. Sous la direction de Pierre Aigrain, ce projet a été accepté par la DGRST. Le CNRS a suivi très rapidement en créant les premiers programmes de recherche intersectoriels, destinés à jeter des ponts entre les départements. Celui des matériaux, l'un des plus importants et des plus stables, a longtemps été dirigé par Jean Hanus.

Ce démarrage des matériaux reste relativement modeste. En France, comme aux USA, il concerne surtout l'enseignement des écoles d'ingénieurs et de certains DEA. Il se réduit bien souvent à une alliance entre métallurgistes et physicochimistes dans une perspective d'ingénieurs. L'électronique reste au départ en dehors du mouvement.
Je pense que l'importance qu'ont prise graduellement les matériaux est venue principalement de ce que c'était un terme commode pour couvrir une large gamme de recherches à la fois interdisciplinaires et débouchant sur des applications pratiques, dont on pouvait affirmer l'importance pour la société et garantir d'un mot le secteur dans les plans et les budgets. C'est incontestablement ce qui s'est produit en France comme à Bruxelles (siège de l'Union européenne) dans les années 1980. La situation a dû être similaire aux USA. Cela explique le ralliement des gens de l'électronique et des semiconducteurs à cette époque.
Ensuite le mouvement s'est affermi avec la création de la Materials Research Society (1973) dont la branche européenne, animée par des physiciens nucléaires de Strasbourg, s'est développée nettement plus tard. La réponse des sociétés de métallurgie en Europe a été de se transformer en sociétés de matériaux et de se fédérer à l'instigation des Britanniques, pour faire front à l'impulsion venue des USA. Même dans la Materials Research Society, on peut noter que des réunions plus « électroniques » alternent avec des réunions plus « atomiques » !
Pour moi, la conclusion est claire : si un minimum de connaissances communes est nécessaire pour tous les gens actifs dans les matériaux, et s'il est utile qu'ils fassent front commun pour défendre ce secteur, il est moins facile de gérer au jour le jour des recherches en commun et il faut tenir compte d'autres forces et d'autres nécessités, dans l'enseignement universitaire notamment. De ce fait je ne pense pas que la notion de matériaux ait le même sens actuellement en France et aux USA.

Deuxième remarque, l'interdisciplinarité, souvent présentée comme caractéristique de la recherche en matériaux, s'est pratiquée bien avant le développement de ce terme. Ainsi la Société française de métallurgie avait, juste après la deuxième guerre, un groupe de physique du métal, présidé par André Guinier et qui réunissait dans des discussions et des colloques tout le gratin d'alors : industriels, gens des organismes, des écoles, des universités, mais aussi des physiciens, des chimistes, des mécaniciens, des cristallographes. Pendant dix ans, entre le milieu des années 60 et 70, la même Société de métallurgie a copatronné avec le CEA (Commissariat à l'énergie atomique) et l'IRSID (Institut de recherche sidérurgique), des écoles d'été annuelles fort suivies. Ces écoles d'été menées par Y. Adda (CEA), Yves Quéré (CEA, puis Ecole polytechnique), et J. Philibert (IRSID puis Orsay) réunissaient de jeunes chercheurs et des gens confirmés des universités, des organismes et de l'industrie. Elles couvraient des thèmes généraux qui seraient maintenant jugés matériaux. A partir de 1969 des groupes dits de Monestier (l'endroit où s'est tenue l'école cet été là) ont fait périodiquement le point sur l'état des recherches dans une dizaine de domaines spécialisés (défauts ponctuels, plasticité, surfaces, etc.). Ces réunions régulières sont maintenant oubliées car elles ont été publiées chacune séparément, en français, par un éditeur différent. Ce qui fait qu'elles n'apparaissent pas comme une série homogène.
L'interdisciplinarité a été aussi renforcée par les Actions Thématiques Programmées (ATP) du CNRS, assez similaires aux Actions concertées décrites plus haut mais dans des domaines plus pointus et variables. J'ai moi-même suscité et présidé des ATP sur les surfaces et sur les agrégats, qui ont fortement développé l'interdisciplinarité de ces domaines en France.
Un dernier aspect de l'interdisciplinarité est la nécessité de collaboration entre chimistes et physiciens pour produire des matériaux et en étudier les propriétés physiques. Dans certains cas, et sans parler de l'approche « matériaux », ceci a été fait sur place, dans le même (grand) laboratoire. Ce fut le cas (peut-être pas si souvent) dans les deux grands instituts de Stuttgart et de Jülich par exemple. A Orsay, notre laboratoire de physique des solides a cherché à résoudre partiellement le problème en implantant de petites équipes de chimistes d'abord dans la production d'alliages métalliques, puis de cristaux liquides, enfin de composés organiques conducteurs. Si ces groupes ont été très utiles, il a été parfois difficile de défendre leurs membres avec succès dans leur commission CNRS respective. Les grands laboratoires de chimie des solides français ont aussi acquis une compétence utile dans certaines techniques physiques.
Une solution très différente et, je pense, de plus d'avenir, est une collaboration entre deux groupes, l'un physicien, l'autre chimiste, sur le développement et l'étude de matériaux nouveaux. C'est de cette façon que Jean Rouxel (Nantes) et Monceau (Grenoble) ont découvert le courant de Frölich des ondes de densité de charge, que Beckgaard (Copenhague) et Jérôme (Orsay) ont découvert la supraconductivité organique (à la suite des travaux d'une ATP sur les conducteurs organiques), etc.
Donc pour résumer, avec la création des DEA, des écoles d'été, les ATP les enseignements et la recherche en matériaux ont été développés en France et assez actifs. Mais ce mouvement est assez difficile à saisir car l'ensemble ne s'appelait pas science des matériaux comme aux Etats Unis.

Troisième remarque : comme les matériaux sont un peu une création américaine, une dynamique américaine, il faudrait éviter de rééditer les problèmes posés par la réduction de l'histoire de la physique du solide jusqu'aux années 50. Le groupe de spécialistes qui avait initialement travaillé à ce projet - principalement anglosaxons et quelques allemands- ont fait une sorte d'hymne un peu excessif à John Bardeen, passant sous silence la plupart des contributions européennes notamment entre les deux guerres. Dans un deuxième temps, d'autres personnes ont été consultées. Alors trop occupé et voyant l'ampleur de la tâche, j'ai refilé la demande qui m'était faite à Guinier qui a pu rétablir un minimum de corrections, sur la conduction électrique des métaux (Linde) ou le magnétisme (Néel), par exemple. Mais le résultat final reste biaisé et j'ai été frappé récemment de voir citer cet ouvrage comme une référence irréfutable. Votre projet aussi est initialement américain et internet est surtout implanté en Amérique. Vous avez donc un biais dont il faudra vous dégager.

BERNADETTE BENSAUDE-VINCENT (BBV) : Pourriez vous préciser ce qu'il en est de l'essor de la recherche en matériaux en France ?

JF : Comme je vous l'ai expliqué, il m'est difficile de vous répondre clairement. Qu'est-ce qui appartient aux recherches matériaux, aux phases condensées, aux solides ? Si on prend l'ensemble, il est considérable et je pense comparable en valeur et en quantité par chercheur à ce qui se fait dans les autres pays développés.
Si vous prenez le sens restreint d'une recherche dans un institut analogue aux instituts de recherche en matériaux américains, je vous répondrai que cela débute bien avant le mot matériaux dans quelques laboratoires industriels comme Saint Gobain, Péchiney, Thomson CSF, CGE Alcatel comme dans les organismes de recherche appliquée, en particulier à l'ONERA (Office national en recherches aéronautiques) et au CEA (Commissariat à l'énergie atomique). Le CEA a eu, dès le départ, des sections de recherche fondamentale mais aussi beaucoup d'activités science des matériaux, où il fallait fabriquer quelque chose pour quelque chose de précis dans un but donné. De même à un moindre niveau, l'IRSID pour la sidérurgie, l'ONERA pour l'aviation et l'Ecole des mines de Paris dans son centre de Corbeil puis de Sophia Antipolis, ont développé assez tôt une approche génie des matériaux, reprise par l'université de Compiègne.

BBV : Pourquoi la science des matériaux s'est-elle mieux développée en Grande Bretagne ?

JF : S'est-elle vraiment mieux développée là bas qu'en France ? Je n'en suis pas convaincu.

BBV : Oui si l'on en croit Robert Cahn.

JF : Je connais Robert Cahn depuis 1948. C'est un métallurgiste très distingué, qui a fait des travaux remarqués dès sa jeunesse sur la polygonisation des métaux écrouis. Ses fonctions d'éditeur l'ont amené au contact d'énormément de choses. Mais il a quand même des limites, comme tout le monde.

HERVE ARRIBART (HA) : Il se pose comme un fondateur de la science des matériaux.

JF : Robert Cahn a certainement contribué à développer une image positive et vivante de la recherche en matériaux. Ceci dit, il faut tenir compte de deux effets d'optique : les matériaux dont il parle dans son livre sont surtout les matériaux de structure. Il y a fort peu de choses sur les semiconducteurs et encore moins sur les supraconducteurs, assez peu aussi sur le magnétisme. On reconnaît là la dichotomie atomes/électrons qu'il est d'ailleurs difficile de maîtriser dans un domaine aussi étendu.
Robert Cahn est maintenant connu par les livres qu'il a édités sur les matériaux. Les auteurs qu'il a sollicités sont loin d'être tous britanniques. En fait, il a, comme je l'ai dit, des contacts depuis longtemps avec la France (où il a été professeur à Orsay trois ans en métallurgie) comme avec les USA et bien d'autres pays. Ses livres reflètent donc la pluralité des pays actifs dans ce domaine avec un biais bien compréhensible pour la Grande Bretagne.

HA : Et connaissez vous John Goodenough ?

JF : Depuis moins longtemps que Robert Cahn mais je l'ai pas mal vu lors de ses séjours à Bordeaux puis à Oxford. Je pense que c'est un chimiste de grande valeur, qui a des idées théoriques intéressantes tout en produisant des matériaux nouveaux.

HA : Pourquoi avez vous choisi d'aller à l'Université de Bristol ?

JF : J'explique cela dans mon discours à la Materials Research Society pour le von Hippel Award en 1988. Je développe aussi ce point dans Graine de mandarin (Odile Jacob, 1995).
J'ai commencé une recherche expérimentale chez C. Crussard au laboratoire de Métallurgie de l'Ecole des mines de Paris, en 1948. Après quelques tâtonnements où je me suis familiarisé avec les instruments, presque tous conçus par Chevenard d'Imply, Crussard m'a donné une petite plaquette d'aluminium recristallisé dont les grains avaient des joints perpendiculaires à la plaquette. J'ai mesuré la variation de l'énergie de joints en fonction des désorientations entre grains et j'ai voulu comparer avec des calculs. A part le cas des faibles désorientations, où on se ramène à un problème de dislocations, rien n'existait alors dans les livres de physique des solides. Seul Seitz considérait l'énergie d'un cristal parfait de métal alcalin. Mais rien n'existait sur les énergies de changement de phase ou sur les énergies de défauts. Je ne pouvais pas progresser dans ce domaine sans avoir compris un peu mieux les électrons dans les métaux, responsables de leur cohésion.
Crussard me présenta alors à son ami Nevill Mott, physicien du solide à Bristol lors d'un de ses nombreux voyages sur le continent. J'étais payé par le Corps des Mines pour faire de la recherche (par le décret Suquet de 1939, applicable à 10% des corps techniques de l'Etat). J'ai ainsi passé trois ans à Bristol à apprendre la physique et à faire un Ph D. Bristol était connue, outre les travaux sur les rayons cosmiques autour du futur prix Nobel Powell, pour les travaux sur la structure électronique des solides (N. Mott) et les dislocations (F. Charles Franck). Mott m'a mis sur un problème fondamental , celui des impuretés. Quand on change la nature d'un atome de métal, qu'on ajoute ou retire un atome de ce cristal, comment les électrons réagissent-ils ? J'ai été le premier à étudier les franges de diffraction ainsi produites autour de l'impureté, d'abord numériquement (à la règle à calcul) dans des études autocohérentes puis par des théorèmes généraux simples que j'ai ainsi découverts. Dans un second temps, revenu à Paris, j'ai compris avec A. Blandin, un de mes premiers thésards, que quand les effets de diffusion par les atomes étaient faibles comme dans l'aluminium, les forces interatomiques étaient additives à volume constant et pouvaient se déduire simplement de la diffusion des électrons par chaque atome pris isolément. Le détour par Bristol m'a ainsi permis de comprendre la nature des forces interatomiques dans les métaux comme l'aluminium et donc de calculer l'énergie des joints de grains.
Avec F.C. Franck j'ai appris les dislocations, un domaine alors en grande expansion. De retour en France en 1852 j'ai continué sur les deux sujets. J'ai d'abord passé une thèse française, pour pouvoir éventuellement entrer à l'Université. Je ne voulais pas réitérer les ennuis de mon grand père, directeur de l'Institut de cristallographie à Strasbourg après avoir dirigé l'Ecole des Mines de Saint-Etienne, mais barré de la Faculté des sciences parce qu'il n'avait jamais passé sa licence ! En 1956, je suis finalement entré à la Sorbonne et en 1959 André Guinier, R. Castaing et moi avons emménagé à Orsay. Pierre Gilles De Gennes nous a rejoints en 1961 et nous avons été un des premiers laboratoires associés au CNRS (le N°2) dépendant de plusieurs commissions.

HA : Quand vous avez eu un laboratoire à Orsay avez vous accueilli des chercheurs de Bristol ou d'Angleterre ?

JF : Nous avons assez vite recruté au CNRS un Ecossais, J. Campbell qui avait fait une thèse expérimentale avec N. Kurti à Oxford dans les techniques nucléaires à basses températures. Nous avons aussi recruté C. Froidevaux, un Suisse issu du Polytechnicum de Zurich, spécialisé en techniques de résonance à Berkeley après avoir lui aussi fait une thèse chez Kurti à Oxford.
Mais c'est au niveau des échanges temporaires que nous avons eu le plus de contacts avec l'étranger, dans les deux sens et la plupart avec des pays industriels. Des thésards étrangers sont venus quand nos groupes théoriques et expérimentaux ont pris de l'ampleur. Dans la vingtaine de mes propres élèves j'ai eu ainsi un Polonais, un Chilien, un Libanais, un Croate, un Allemand. Ce dernier H. Schulz, sans doute le plus brillant et le dernier de mes thésards, est malheureusement décédé récemment.
Avec l'Angleterre, j'avais des relations privilégiées avec N. Mott, devenu mon beau-frère, chez qui j'ai passé en famille de nombreux étés, surtout à Cambridge. Par lui j'ai développé des contacts avec P.B. Hirsch, S. Zimian, V. Heine. J'ai maintenu de fréquents contacts avec F.C. Franck à Bristol. F.R.N. Nabarro et R.W. Cahn ont été aussi visiteurs à Orsay.
A Bristol, où il y avait peu de thésards britanniques à l'époque, j'ai établi autant de liens avec les visiteurs étrangers, notamment des spécialistes allemands des défauts cristallins comme A. Serger, G. Leibfried, D. Kuhlmann-Wilsdorf. Enfin j'ai eu très tôt des contacts avec nombre d'Américains, dont C. Kittel, H. Brooks, W. Kohn, N. Bloemberger ont le plus compté pour mon début de carrière.

HA : Pour autant que je m'en souvienne il n'y avait pas beaucoup d'étudiants étrangers dans le DEA de physique du solide à Orsay, du moins l'année où j'y étais ?

JF : En effet on en a eu que quelques uns par an, surtout d'Europe de l'Est et des pays méditerranéens, parsemés de quelques Allemands, Hollandais, Chinois et une année deux Américains du Nord. Il n'y avait pas d'Anglais. Le DEA qu'on a créé à Orsay avec Guinier et Castaing en 1959 ne s'intégrait pas dans le cadre de formation des thèses anglaises. Leurs thèses se faisaient beaucoup plus vite en trois ans au maximum après une licence en 3 ans. Donc c'est après leur thèse que les Anglais venaient et nous nous envoyions nos propres étudiants en post-docs à l'étranger. Cette formule d'échanges de post-docs me semble de toutes façons meilleure. Il faut dire aussi que le DEA de physique des solides couvrait toute la région parisienne et que notre laboratoire recrutait (et recrute) aussi sur d'autres DEA de la région parisienne ou de province.

BBV : Votre enseignement de DEA était-il expérimental ou théorique ?

JF : Après un démarrage officieux en 1955 à Paris avec l'aide de Roman Schmolukovski nous avons eu longtemps trois cours de base, essentiellement théoriques : cristallographie, phénomènes de transport, structure générale des solides, assurés au départ par Guinier, Aigrain et moi-même. Seul Guinier avait des travaux pratiques. A partir de 1961, De Gennes a fait un cours de physique quantique. Par la suite nous avons demandé aux étudiants de faire un court stage dans un laboratoire et de rédiger et soutenir un mémoire à l'issue du stage. Mais nous n'étions pas un DEA classique, la plupart des DEA ayant la moitié de leur temps en laboratoire. Dès le début nous avons aussi développé des cours complémentaires de deuxième année beaucoup plus spécialisés et variant d'une année à l'autre. C'est ainsi que sont nés de nombreux ouvrages comme les premiers livres de De Gennes mais aussi des introductions par différents auteurs aux défauts ponctuels, à la mécanique électronique, aux ondes de spin, à la supraconductivité, le cours de G. Toulouse sur les statistiques en dimensions fractionnaires, le livre de M. Kléman Points, lignes, parois et bien d'autres.

BBV : Avez vous développé des liens avec les chimistes d'Orsay ?

JF : J'avais au départ des liens avec P. Lacombe qui dataient de l'Ecole des Mines. Je connaissais Chaudron et ses élèves, notamment Collongues et surtout Revcholevski qui collabore depuis longtemps avec Jérôme sur les supraconducteurs. Je connaissais beaucoup de gens à Vitry, particulièrement D. Gratias, dont j'ai suivi le démarrage pour sa thèse sur les structures incommensurables de surfaces et surtout sa découverte des quasicristaux. Les chimistes avaient au départ, en France, une plus longue tradition de théorie quantique et j'ai eu des contacts fructueux dans les années 60 avec plusieurs chimistes de mon âge à Orsay. Il en a été de même avec la chimie physique, initialement brillante à Orsay dans des domaines originaux comme les cristaux plastiques ou la tenue aux irradiations des molécules organiques, deux domaines dispersés par la mort ou le déménagement des acteurs, à part la réaction photographique de Mme Belloni. Quant à Henri Kagan dont on parle beaucoup ces jours-ci, je l'ai surtout connu et apprécié au Conseil de Troisième Cycle à Orsay quand je le présidais.

BBV : Et des liens avec les industriels ?

JF : Soyons clair : je suis un modeste théoricien des solides, pas un grand manitou des matériaux. Ceci dit, au laboratoire de métallurgie de Crussard j'ai eu l'occasion de rencontrer des métallurgistes industriels comme Herenguel et surtout Chevenard. Au retour de Bristol, j'ai fait systématiquement le tour des laboratoires industriels ; Péchiney à Chambéry a même cru que je venais espionner ! C'est l'époque où j'ai fait deux expériences extrêmes. Un sidérurgiste très distingué m'a demandé de visiter le centre de recherche d'un de ses groupes sur les ferrites ; il s'agissait en fait seulement de fabrication et on me suggérait d'espionner Philips, ce qui n'était pas dans mes cordes. Un jeune ingénieur italien de St Gobain (alors au Sud du Brésil) m'a spontanément invité à visiter le laboratoire et m'a parlé de recherches intéressantes qu'il avait engagées sur les centres colorés des verres trempés ; jusqu'à sa mort prématurée, j'ai ensuite reçu chaque année un cadeau, production Saint-Gobain.
Plus sérieusement, j'ai gardé deux contacts suivis mais avec des organismes de recherche appliquée : avec l'IRSID où j'ai été conseiller pendant près de 30 ans et avec le CEA où j'ai été également conseiller de 1955 jusqu'après ma retraite. E. Grison, qui m'a recruté, dirigeait la métallurgie civile de l'uranium et du plutonium (qui donnera le MOX). Mais très rapidement, j'ai débordé vers des problèmes de chimie physique et la physique de Saclay. Mon activité a été essentiellement fondamentale, au CEA comme à l'IRSID. J'y ai dirigé des thèses toujours dans des domaines fondamentaux : Y. Quéré par exemple sur les défauts d'irradiation dans les métaux, travaux sous-tendus par les questions de fragilité, gonflement, fluage sous irradiation dans les réacteurs nucléaires ; M. Kléman sur les phénomènes magnétoélastiques qui jouent un rôle majeur dans les mémoires magnétiques, en couches minces. J'ai aussi été longtemps au conseil d'administration du LEP (Laboratoire d'études de Philips en France). J'ai présidé les conseils scientifiques de Saint-Gobain et de France-Télécom, après celui du CENT (Centre national d'études en télécommunications) de Bageux sur les semiconducteurs.

BBV : Ces présidences étaient-elles honorifiques ou plutôt directives ?

JF : Comme toujours c'était ni blanc ni noir. Le CNET Bagneux puis France Télécom sont de bons exemples. Les créateurs du CNET Bagneux, M. Bernard et J. Serphagnon, avaient le souci que le laboratoire garde une excellence fondamentale tout en s'ouvrant largement sur la recherche appliquée. Présidant alors la Commission de physique des solides du CNRS, j'ai facilité la création d'un laboratoire associé CNET/CNRS dont j'ai présidé le Conseil scientifique durant plusieurs années. Ces réunions annuelles obligeaient les gens de laboratoire à rendre compte et les dirigeants du CNET à prendre position sur le développement du laboratoire. Avec l'adjonction d'une section venant purement des applications, puis d'un groupe propre du CNRS, l'ensemble était, lors de la création de France-Télécom l'un des meilleurs laboratoires de semiconducteurs hors silicium en Europe (composés II-V et organiques essentiellement).
J'ai quitté le CNET-Bagneux pour devenir le premier président du Conseil scientifique de France Télécom. Là les problèmes étaient d'un tout autre ordre, techniques d'abord, puis rapidement économiques et politiques. Dans un premier temps, quand France Télécom était nationalisé, nous avons de nouveau obligé les gens à présenter leurs problèmes et leurs solutions et nous avons œuvré pour l'ouverture de France Télécom à la recherche française extérieure. Le temps de la privatisation, avec le développement d'Internet et du portable, a conduit à l'abandon des grands secteurs de la recherche - y compris au Centre de Bagneux - et à la mise en sommeil de réflexions à long terme sur les nouveaux matériaux (organiques en particulier) comme sur les réseaux. Nous avons éclairé, dans notre mesure, sur les dangers tant immédiats qu'à long terme et cherché à éviter que France Télécom se referme sur elle-même au point de vue recherche.

HA : Vous avez mentionné les deux orientations de vos recherches vers l'électronique des métaux et les dislocations. J'ai le sentiment qu'à un moment vous avez favorisé le premier et un peu abandonné le second.

JF : Depuis Bristol, j'ai toujours eu une activité de recherche sur l'électronique des solides. J'ai essayé de développer des modèles approximatifs mais simples, compréhensibles et même utilisables par des non-spécialistes. Je suis un vrai élève de N. F. Mott en ce que, dans un domaine complexe où 1024 particules sont en interactions fortes, des caricatures faites sur un dos d'enveloppe me semblent pouvoir être plus pertinentes que des collections de papillons, photos léchées à l'ordinateur mais souvent peu généralisables. Après de nombreuses études sur les alliages métalliques développées avec mes thésards, je me suis intéressé à la cohésion et au magnétisme des métaux purs, dont les électrons de valence sp, d ou f sont progressivement localisés et demandent des approximations différentes. Je me suis aussi intéressé aux covalents sp qui gardent, avec l'ordre local, une bande interdite de covalence même dans l'état amorphe. Plus récemment je me suis intéressé à la physique, très riche, des surfaces et des agrégats, sans oublier des sujets à la mode comme les supraconducteurs ou les quasicristaux.
J'ai abandonné pour un temps les dislocations après la seconde édition de mon livre (1964) sous la pression des événements et puis parce que j'avais le sentiment de n'avoir plus trop à dire sur le sujet, du fait notamment que je n'avais pas développé de groupe expérimental à Orsay sur ce sujet. Mais j'y suis revenu avec les cristaux liquides. De Gennes avait été persuadé par G. Durand, rentrant de Harvard, de l'intérêt de ce domaine mésoscopique justiciable de méthodes d'analyse analogues à la méthode qu'il avait utilisée pour les supraconducteurs. De Gennes s'est penché sur l'étude des dislocations de ces corps. Mais c'est plutôt Maurice Kléman (laboratoire de Physique des solides d'Orsay, puis laboratoire de minéralogie et cristallographie de Jussieu) qui a développé ce domaine en liaison avec F.C. Franck. Je me suis remis à ce sujet, notamment aux possibilités de dislocations de rotation caractéristiques de certaines de ces phases. Les réseaux plus ou moins réguliers de telles dislocations posent des problèmes topologiques intéressants, mis en jeu dans certaines phases mésomorphes dites cholestériques (germes, phases bleues) mais aussi dans les quasicristaux. J'ai gardé le contact puisque cette année j'ai rédigé des préfaces substantielles pour deux gros livres sur la dislocation dans les cristaux liquides. J'ai fait aussi un commentaire introductif à un gros bouquin sur l'écrouissage des métaux qui reste toujours un problème ouvert.

HA : Vous avez évoqué les supraconducteurs à propos de De Gennes. Comment avez vous vécu l'arrivée des cuprates et l'excitation sur les supraconducteurs ?

JF : Les Français auraient dû découvrir les supraconducteurs cuprates si les chimistes des cuprates avaient accueilli des physiciens. C'est un beau contre-exemple de l'interdisciplinarité.
J'étais intéressé par les supraconducteurs organiques. Il y a pas mal d'analogies avec les cuprates car ce sont des structures anisotropes faites de chaînes ou de plans d'atomes parallèles ou faiblement liés. Donc d'un certain point de vue les oxydes m'ont attiré toute de suite un peu comme une extension des organiques de Jérôme (J. Denis Jérôme, laboratoire de Physique des solides d'Orsay). Mais je m'intéressais aux oxydes dans un esprit assez conservateur. Au lieu d'aller vers des choses nouvelles et compliquées, je préférais voir si une approche BCS classique ne pouvait pas marcher. Je pensais notamment que les corrélations électroniques dont B. Schrieffer, M. Rice et P.A. Anderson faisaient tout un plat, existaient certainement mais peut-être pas de façon plus notable que dans les métaux de transition comme le nickel ou le chrome que j'avais précédemment étudiés. Je ne crois donc pas aux constructions magnifiques de Phil Anderson pour les oxydes. Mais ma position est controversée : on m'a demandé près de 100 tirés-à part d'un article de revue écrit l'année de ma retraite ; mais on ne me cite jamais ! D'une façon plus générale, je pense que trop de gens se sont lancés dans une quête sans espoir d'un second Nobel après Müller.

BBV : Et comment voyez vous le futur des supraconducteurs ?

JF : Il n'y a pas encore d'applications industrielles mirobolantes. Il faudra du temps ! Mais les supraconducteurs ont deux apports quasi certains :

ils permettront peut-être de petits montages dans des systèmes électroniques de faibles puissances. De ce point de vue les gens de la Bell (Batlog, Scön) ont montré récemment une voie certes difficile à mettre en œuvre mais très intéressante.
ils ouvrent la voie à des méthodes qu'on pourrait utiliser en d'autres domaines. Par exemple, Fischer à Genève fabrique des couches atome par atome. L'idée est de faire des composés à la demande avec des structures choisies, des composés qui n'existent pas à l'état naturel, tout à fait en dehors des équilibres thermodynamiques. Par le choix de ionocovalents qui ont une interdiffusion atomique faible, les interfaces chimiques entre couches gardent leur netteté.

HA : Quelle fut d'après vous la démarche de Müller à Zurich ?

JF : Müller était un spécialiste très connu des ferroélectriques. Il est allé à une école d'été à Cargèse où des théoriciens de Grenoble ont évoqué la possibilité pour des ferroélectriques de devenir supraconducteurs. A son retour, il a cherché lesquels conduisent l'électricité et il a obtenu une supraconductivité à assez haute température. Le tort de Müller a été de s'accrocher à l'idée de ferroélectriques à laquelle personne ne croit plus guère.

BBV : Pensez vous qu'il y a un lien historique ou logique entre la supraconductivité et la conductivité ionique qu'on a appelée pendant un temps superconductivité ionique ?

JF : Il n'y a aucun lien. L'analogie des noms est trompeuse. La conductivité ionique est un phénomène atomique classique, alors que la supraconductivité est de nature quantique et électronique (malgré Müller).
Par contre, les superfluides, ou liquides quantiques ont un lien avec les supraconducteurs, rendu possible par la légèreté des atomes mis en jeu.

HA : Quelle est votre attitude à l'égard des instruments en général et des grands instruments en particulier ?

JF : Je suis un pur théoricien mais, comme De Gennes, j'aime être entouré d'expérimentateurs. A Orsay, où De Gennes nous a rejoints en 1961, on a recruté des expérimentateurs pou compléter les groupes déjà existants de A Guinier et R. Castaing. C'était difficile car il y avait en France peu d'expérimentateurs qualifiés en structure électronique des solides, surtout des métaux. Les premiers ont été J. P. Burger, puis Etienne Guyon et C. Froidevaux, un Suisse que nous avons attiré par un poste de professeur d'échange et Campbell, un Ecossais invité par le CNRS. De toute façon il s'agissait d'expériences avec de petits instruments.

Quand j'étais conseiller de la DRME (Direction de la recherche militaire et des études) j'ai facilité l'équipement de nombreux laboratoires, notamment en province, couplés à des programmes de recherche fondamentale. Il s'agissait de ce qu'on a appelé plus tard les « instruments mi-lourds », basses températures, microscopie électronique, appareils de résonance... C'était d'une certaine façon prendre le relais des contrats militaires américains qui ont aidé beaucoup de mes collègues à démarrer la recherche fondamentale après la guerre.
Quant aux grands instruments, j'ai toujours pensé que, comme la langue d'Esope, tout dépendait de la façon de s'en servir. Collectionner des spectres de phonons ou de neutrons pour un composé ou un autre, n'a pour moi guère d'intérêt et prend beaucoup de temps. Mais le programme de l'Institut Laue-Langevin (ILL) à Grenoble ne fait heureusement guère de place à ce genre d'activités. J'ai toujours pensé que ces grands instruments peuvent offrir des possibilités absolument inédites pour la physique, la chimie, la biologie en général et pour les matériaux en particulier. J'ai donc travaillé dans ce sens en plusieurs occasions.
A Orsay, par exemple, j'ai suscité la réunion de physiciens des particules et de physiciens des solides qui a permis d'ouvrir l'accélérateur nucléaire au rayonnement synchrotron, c'est à dire à la naissance de LURE (Laboratoire d'Utilisation du Rayonnement Electromagnétique). Sous la pression du radiobiologiste V. Luzzati, que j'avais connu au Conseil scientifique de l'ILL, et de mon jeune collègue Y. Farge de notre laboratoire, j'ai convaincu mon ami Laguarrigue, directeur de l'accélérateur linéaire, de tenter cette expérience. J'en ai suivi les premiers pas.
En 2000 je suis intervenu auprès du gouvernement pour le faire revenir sur sa décision d'annuler le projet SOLEIL, successeur de LURE. Cette démarche avait trois raisons :

Il faut quelques très grands instruments (comme l'ESRF de Grenoble pour le rayonnement synchrotron) fonctionnant à l'échelle européenne. Leur fonction est de découvrir des techniques nouvelles en physique et en chimie ce qui est rendu possible par les propriétés spécifiques (polarisation, cohérence, hachage temporel) et par l'accroissement de la puissance et la définition de ce rayonnement comparé aux sources classiques ou aux lasers. Mais un tel équipement est trop vite saturé pour répondre aux besoins à l'échelle nationale, où il faut former des chercheurs et appliquer ces techniques, dans des expériences souvent longues. Tout cela coûte de l'argent mais si l'on considère le nombre de personnes engagées dans ces expériences ce n'est pas exorbitant.
Le synchrotron est aussi utile aux études biologiques. Il y a là un domaine en plein développement où le synchrotron n'est pas actuellement remplaçable, notamment pour l'étude structurale de molécules complexes. On peut noter qu'il y a là une extension nécessaire de la notion de matériaux : par exemple, les techniques de croissance des cristaux de molécules à longues chaines posent des problèmes spécifiques qui devraient être analysés en priorité et où la participation de physiciens et de chimistes est indispensable.
Enfin ces grosses machines sont aussi des lieux de rassemblement interdisciplinaire...du moins si on s'y prend bien. Il ne suffit pas d'installer des machines pour générer de la collaboration.

BBV : Quelle fut votre attitude à l'égard de la politique française sur les matériaux ?

JF : Je regrette que le gouvernement ait abandonné pour la recherche son affichage d'une priorité matériaux. Je suis convaincu que c'est un secteur essentiel de la recherche où le fondamental et les applications, les universités, l'industrie et les organismes de recherche appliquée peuvent et doivent se rencontrer sur un pied d'égalité. L'idée que l'on puisse développer les sciences de l'information ou les sciences de la vie sans une solide base matériaux est une idée de pays sous-développé !
Il me semble aussi clair que le domaine général des matériaux est en évolution rapide, avec une importance croissante des secteurs matériaux organiques, composites à l'échelle atomique, importance croissante aussi du mésoscopique. Tout pays qui ignorera les problèmes de « hard » en ne privilégiant que le « soft » ou le « bio » perdra à la longue dans la compétition.
Je suis aussi pour l'interdisciplinarité qui sous-tend la recherche en matériaux. De ce point de vue que l'on ait développé ce facteur dans les maitrises universitaires, que l'on ait créé aussi des enseignements d'écoles d'ingénieurs et des DEA spécifiquement matériaux me semble une bonne chose, comme aussi la réussite de certains instituts CNRS-universités ou CNRS-industrie de matériaux.
Mais ce n'est pas la panacée : le secteur est tellement énorme qu'il faut forcément se spécialiser. Je crois au travail en commun de chercheurs formés de différentes façons ; je crois aux échanges de chercheurs, aux collaborations. Mais ceci n'implique pas pour tout le monde l'abandon des grandes divisions de spécialistes, que ce soit à l'Université ou au CNRS. Je regrette pareillement l'abandon de laboratoires fortement affichés dans certaines branches de la physique et de la chimie.
Enfin je pense que, particulièrement dans le secteur des matériaux, le développement instrumental - des microscopes atomiques au rayonnement synchrotron - a joué un rôle majeur dans les développements récents. Et rien ne permet de dire que cette dynamique très interdisciplinaire, va se tarir.

Fin de l'enregistrement

Chère Madame Bensaude-Vincent,

J'ai lu avec attention et intérêt votre analyse sur « Materials Science in the United States ». Je pense que vous avez fait un effort de synthèse remarquable sur un sujet aussi diffus et la lecture de votre texte avant notre interview aurait peut-être permis de mieux polariser notre discussion.

J'ai quelques remarques générales : le titre comporte « sciences » mais le texte parle autant (dans la 2° moitié) d'« engineering ». D'autre part le texte déborde largement des US.

Je pense que la « dynamique »matériaux s'est développée aux US par suite d'un manque d'instituts ou de grands laboratoires de recherche universitaire en dehors des domaines à grands instruments comme le nucléaire, les hautes énergies, le spatial.... La situation est un peu similaire en GB (à part des centres peu nombreux comme Cambridge, Oxford, Bristol...), mais différente en Allemagne (avec les Max Planck), en France : à partir des années 40 (LP CNRS ) et surtout 60 (LA CNRS).

Il y a d'autre part certains manques. Vous ne parlez pas des cristallographes qui, en GB, en Allemagne et en France mais aussi aux USA, ont joué un rôle pionnier dans l'étude des cristaux, des défauts cristallins, des amorphes, des changements de phase comme dans le développement des instruments (neutrons aux USA), électrons en GB, rayonnement synchrotron (en Italie puis aux USA et en France...).

La césure entre matériaux de structure et matériaux électroniques, très dommageable aux deux, particulièrement forte aux USA n'est que notée au passage. Enfin des domaines certes très européens au départ comme les agrégats et les quasicristaux manquent un peu.

Une étude aurait pu être faite sur l'analyse des relaxations plastiques en front de fissure. Celle-ci avait, avant le développement des dislocations, pris un virage très fondamental, barré avec les accidents des Comets par l'urgence de trouver des parades pratiques. On est revenu aux analyses macroscopiques, avec des paramètres tirés de l'expérience mais qui varient avec les conditions de fracture. Ce n'est qu'assez récemment, avec des gens comme Pinault à l'Ecole des mines – Corbeil, qu'on est revenu à des analyses plus microscopiques et physicochimiques. Cet aller-retour est, je pense, typique de bien des domaines. Il souligne une difficulté fondamentale de traiter un domaine comme un tout. C'est le dialogue qui doit être perpétuel entre les progrès fondamentaux et les applications. Sauf cas très rares, je ne crois pas qu'un seul institut des matériaux, universitaire ou industriel, ait créé de toutes pièces et en allant jusqu'à l'application une seule découverte utile.

Enfin sous cette pression US notamment, c'est le soutien de toute recherche dans le « hard » qui a été compris comme « materials », en opposition avec le « soft » et le « bio ». Ces dernières années, ce sont ces deux autres domaines qui ont eu la suprématie. Mais je ne pense pas la situation viable très longtemps.

Bien cordialement

Jacques Friedel

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Entretien avec Jacques Friedel, par Hervé Arribart et Bernadette Bensaude-Vincent, 17 octobre 2001.

Lieu : Académie des Sciences, France.

Support : enregistrement sur cassette.

Transcription : Bernadette Bensaude-Vincent

Hervé Arribart.

Édition en ligne : Sophie Jourdin.

DRESSELHAUS Mildred S., 2001-10-25

Sophie Jourdin — 2011-06-18T22:59:55Z

Mildred Dresselhaus est née en 1930 à Broolkyn, New York. Elle étudie la physique au Cavendish laboratory de l'University of Cambridge en 1951-1952. De retour aux États-Unis, elle obtient en 1953 un Master Degree au Radcliffe college et un PhD en physique à l'Université de Chicago en 1958. Elle se consacre alors à la physique du solide, à la supraconductivité et à la magnéto-optique. Elle intègre ensuite le Lincoln lab du Massachusetts institute of technology (MIT). Avec son mari Gene Dresselhaus, elle oriente alors ses travaux vers l'étude de la structure électronique des semi-métaux – et en particulier du graphite. En 1967, Mildred intègre le département d'Electrical engineering du MIT comme Professeur associé. Elle dirige ensuite le Center for materials science and engineering du MIT. Elle devient Professeur de physique en 1983. En 1985, elle est la première femme à être nommée Institute Professor - le plus haut titre d'un membre de la Faculté du MIT. Mildred Dresselhaus accède ensuite à des postes à haute responsabilité en matière de politique scientifique et de financement de la recherche où elle soutient activement les programmes de recherche en nanotechnologies. Milldred Dresselhaus est particulièrement connue pour son travail sur les propriétés électroniques et photophysiques des allotropes du carbone : le graphite et ses composés d'intercalation, le carbone microporeux, le charbon activé, les fibres de carbone, les aérogels de carbone, les fullerènes, les nanotubes de carbone et les matériaux thermoélectriques de basse dimensionnalité (de zéro- à 2-dimensions). Mildred Dresselhaus a coécrit plusieurs livres sur la science du carbone. Elle a aussi travaillé sur des matériaux autres que carbonés, tels les nanofils de bismuth. Elle a reçu de nombreuses distinctions scientifiques, et a été récompensée à plusieurs reprises pour ses efforts visant à promouvoir la participation accrue des femmes en sciences et en ingénierie. Enfin, "Millie" a encadré plus de 60 PhD, a quatre enfants adultes et plusieurs petits-enfants.

Biographie détaillée

BERNADETTE BENSAUDE-VINCENT (BBV) : How did you make the choice of superconductivity at the University of Chicago in the 1950s ?

MILDRED DRESSELHAUS (MD) : We were encouraged to be independent. Brian Pippard from Cambridge was there for a year and helped define a topic for my thesis. He had been working on Fermi surface of copper. He suggested studying the response of a superconductor in a magnetic field. I made many measurements with various materials in various conditions. And I got unexpected results.

BBV : Was it before the BCS theory ?

MD : Yes it was before the BCS theory and when I published my results Bardeen became interested in them because they could not be explained by their theory. He gave the problem of finding an explanation for it to someone else. I worked with my husband on the model but we did not get a good one. Somebody solved the problem 20 years ago. It was not a consequence of BCS and it was not an important effect for superconductivity.

BBV : What was the situation at the Lincoln Lab when you moved there ?

MD : It was a Defense Lab there was a bunch of interesting projects going on. These were the wonderful years in solid-state physics. Lasers came. I was given so much freedom that I did not have to work on lasers.

BBV : How did you choose your new research topic ?

MD : It was a wonderful career change. I started up magneto-optics. There were new techniques to be learnt, optics in particular. I was working at the High Field Lab, in the basement of Building 4. John Goodenough was my neighbor. I wanted to be independent. Each material has its material science. I decided to work on graphite. There was no competition at that time. The materials science on graphite came from the UK. A highly oriented pyrolytic graphite came from Imperial College in London. The synthesis of diamond had raised interest in the phase diagram. There was an interest in carbon because of its different phases, interesting especially for space programs.
For my experiments I needed a good crystalline structure for the electrons to circle. For the theory problem Joel McClure from Chicago University helped me. A paper was published in the IBM Journal for Research and Development in 1963. Then every year we improved the model. With my second graduate student we turned the established view of the structure of graphite upside down : we put holes were electrons were supposed to be and vice versa. The paper came out in 1968. It turned out to provide the explanation of many effects. It was a real pleasure to hear McClure at the Conference of Low Dimensional Materials in 1970.

ARNE HESSENBRUCH (AH) : Did you have any connections with the Interdisciplinary Laboratory that was set up at MIT in these years ?

MD : I had contacts with A. von Hippel. He was a good friend. The whole idea that Materials Science was interdisciplinary was his idea. He had suggested interdisciplinary laboratories in 1936 and WWII reinforced his view. He started an interdisciplinary laboratory of his own. The Magnet Lab where I was working was separated from von Hippel's. Ben Lax had started a new interdisciplinary lab with Defense money.
I was at home in an Interdisciplinary Lab. My PhD thesis was prepared in an interdisciplinary environment. The Institute of Metals at Chicago University had been sponsored by industry. There were chemists, physicists, all disciplines. The Institute's chair, Cyril S. Smith, advocated interdisciplinarity. He became an historian like his wife in the last 20 years of his life. He did both physics and history.
At MIT, Gordon Brown, the Dean of Engineering, had the idea that engineers should think like physicists. I was asked to teach physics to engineers not in the physics department. This is the MIT tendency to emphasize the practical side rather than the theoretical side.
I had no prejudice for engineers because I needed them for what I was doing. I was affiliated with Electrical Engineering before I got a Chair.

AH : What was the situation when you became Director of the MSE Department in 1977 ?

MD : I was the 3rd director. The Lab was in big trouble because the NSF grant was about to be lost. I tried to keep funding coming in like all directors.

BBV : How did you come to the subject of intercalation compounds ?

MD : I entered the field in 1964. Ted Gaballe of Bell Labs had discovered superconductivity in alkali metal intercalated graphite. How could it be superconducting when none of its constituent were ? He knew my work on the electronic structure of graphite. So he asked me to look at the structure after intercalation. I had no idea of what the experiments should be. In 1971 Moore from Imperial College did the first experiment. So in 1973 I decided to the same with optics.
I wrote a proposal to get funds after some exploratory work. For the first time the proposal was refused. The reason was that my proposal concerned a complicated chemistry that I could not possibly get into : I did not get the money. I received my first grant on intercalation in 1977.

BBV : What was the situation in intercalation compounds when you entered the field ?

MD : There was an important conference in France at [?] near Nice organized by Jack Fischer and Vogo, a company manager who was influential in raising money. In fact the participants did not know each other and they started talking together. This conference had a great scientific impact. I wrote a review article for my students in 1978 that was published in 1981. It turned out to be quoted often, and often because I had few results to report. I pointed out it should go like this and that was the way it did go.

AH : Did you interact with Stan Whittingham ?

MD : Whittingham was there but I had no connection with him

BBV : Did you meet with Jean Rouxel ?

MD : Oh yes, I met him in Nantes two months before his death.

AH : Who were the leaders in intercalation compounds ?

MD : Researchers in few countries are active in this field. The US has been active for a time. France had been active long before the USA and to a certain extent Germany also. Japan entered the field later with batteries but are still there. The first patent was taken in 1972.
We worked on intercalation compounds until 1989. Then I stopped because I did not have ideas big enough. You know the MIT rule : each PhD thesis should be innovative, bring something new.

BBV : Would you say that conferences and review essays were crucial in the emergence of this research field ?

MD : Yes review essays are a pedagogical style useful for shaping fields. I was asked to do the same for fullerenes and later for carbon fibers.

BBV : You've had a number of international collaborations. Did you notice different national styles in the domain of Materials Science and Engineering ?

MD : There are more personal styles than national styles. Science is a universal language.

Fin de l'enregistrement

BERNADETTE BENSAUDE-VINCENT (BBV) : So, we want to focus on certain materials on this site, because we want to discover, especially because it's imploding or exploding and one major problem, we have always put some stuff on on solid state batteries, intercalation compounds that you know very well.

MILDRED DRESSELHAUS (MD) : Yes, I know my contribution to the battery business is much more limited than the big deal of intercalation physics.

BBV : Yes, and also you've been working on superconductivity and especially materials when it was quite unusual and in the 1950s, so if you could just tell us, try to remember, the situation with superconductivity in the late 1950s when you came to Chicago University.

MD : OK so that's where you want to start... well that's kind of the beginning of my foray into materials science. So I was a graduate student at the University of Chicago and looking around for research topics because at the University of Chicago at that time the students worked very independently. They found their own topics and figured out how to work them out and they basically did everything, sort of, very much different from today. But I was a special case, so I did it even more independently than others who did it independently. It was a little bit of a sociological thing (I don't know if in the history of science, you like to have a lot of things that we don't report in our regular papers...). I had an advisor that believed that women should not be graduate students, and that it was a big waste of resources to have us, there were very very few of us at that time, about two percent of the graduate student body nationwide - in these fields. So, because I got so much harassment from him, I stayed away from him therefore I worked a lot more independently than I would have, so I didn't have many people to go to to ask questions. He was the only advisor for materials physics or solid state physics. Well I stumbled upon this field partly because of a visit of Brian Pippard who came to the University of Chicago in 1955 for a year to work out the Fermi Surface of Copper, which was a big breakthrough, it was how to do an experiment back then to predict in detail and also measure what was there. So he was there, and he was a big man also with superconductivity at that time, so he interacted with me a lot for the year I was there and we started on this project, he gave me a bunch of ideas, which was very helpful. So it wasn't that I was totally in a vacuum because it started out with an interaction. Then he left, to go back to Cambridge University, and I stayed on and we had intermittent contact by letter, or maybe we had three or four letter exchanges until my thesis was done so it wasn't very much. But for me, I learned, and reading the papers that he and others had written that you could measure something about superconductors by measuring microwave properties. So that's what I learned from him and then formulated a problem to see what a magnetic field does. As you know magnetic fields kills superconductivity at the transition temperature. When you put on a high enough magnetic field, it's the end of the superconducting phase - and it goes normal. So my project was to monitor what happened on the way to ending superconductivity, on the way to the phase transition. And so I measured several materials. My main material was tin because it was a convenient temperature range and you could make the samples pretty easily. But I also studied other samples.... (MD turns off machine). Okay it's off. So I had magnetic field and different superconducting materials with different transition temperatures, and therefore also critical different magnetic fields. I did different orientations of the magnetic field. You know... all the various things you might think of, but I was stuck with one frequency range, because when you build microwave apparatus you're in one frequency range because everything hooks together and this was all homemade equipment because I had no money. But that was the time that you made your own equipment, it was all war surplus stuff that I found in some kind of stock room and throw it away here or there, and most of my equipment was like that, the rest of it I just made in the shop. So I learned how to do that get people in the shop to get me some instructions.

ARNE HESSENBRUCH (AH) : So you did have help on that score at least.

MD : No, I built it myself and designed it, but I had instruction because I never built equipment, I was just a graduate student I never was learning how to do all of this. But people were very helpful, so I got a lot of training like that, but that was the way we did a thesis in that time.

BBV : And did you have any idea of the BCS theory ?

MD : No it wasn't yet, no that came at the very end. So I go along here and I came up with some results that were somewhat counterintuitive. Because I expected that when you go from here to there it would be a continuous thing but instead I'm going toward the normal state before it got to the normal state it got sort of more superconducting, before it went normal. So it was a kind of anomalous effect. I saw it under many conditions and it always would seem to be there. And that was before BCS. I had all these results before BCS and then when BCS came out, BCS had nothing to say about anything anomalous like this. So, Bardeen was actually very interested in my results, because it couldn't be explained by his theory. Bardeen is B of BCS, a Senior person. So he invited me down to University of Illinois to talk to BCS. But I gave a colloqium there as a graduate student - which was pretty amazing - and I just remembered that because I just did a lecture series earlier this week at the University of Illinois, and I could tell them I was there in 1957, giving a lecture, and that I'm still alive and kicking ! They were kind of interested in that. So, well he got interested in my effect and he gave somebody else a project of trying to develop a theory, a detailed theory of application of BCS to microwaves and magnetic fields, et cetera. So it started a research direction for him, and from the experimental side, Pippard was surprised at what I got, so he assigned this project to two other students both of whom became probably people that you're interviewing, became well known in their own right.

AH : This was back in Cambridge then, right ?

MD : Well, it's a little more complicated. One of them was Paul Richards, who was an American who happened to be there, he may be on your list of people that you're interviewing. He was a postdoc, maybe he was a graduate student, I think he was a postdoc at the time, working in the Pippard group. So he did it at one frequency and Brian Josephson was another person probably on your list, he did it at another frequency after Richards. Paul Richards was, after me, he did it at a different frequency. One did lower, one did higher, something like that. They got basically the same results, more or less. Of course, different frequencies, different circumstances. So that was what happened and now their results spilled over into the 1960s, and my papers were published by 1958. They went on for maybe another three years, in different frequency ranges doing complementary experiments. But what happened to me, I didn't stay with this project for very long. I wanted to do more with it and I tried to develop some model with my husband who I got married to in 1958. So we worked on this, I don't know that we really got a good model, we didn't get a model for it, I would say we tried to follow up and improve what we had done.

AH : Sorry, your model, did you incorporate BCS and then try to also explain the effects from your experiment ?

MD : Yeah, what we were trying to do, take into account the details of fields and external fields, and we had RF fields [radio frequency fields] and external fields. We had different directions, RF fields and external fields.

AH : So what was your model ?

MD : I don't remember a whole lot about what we did at that time ! So many years ago ! And part of the reason I don't remember so much about it is that it didn't really have a big impact on anything. And for me, I had to switch fields, because when I got my next first job that was at Lincoln lab, I was told that that wasn't an area to work on because everything was solved. Of course my problem wasn't solved but it turned out that it was actually solved by somebody maybe ten or twenty years later... quite a long time later. And it turned out to be kind of an obscure, not so interesting effect that didn't have that much to do with BCS theory, but had something to do with the intricacies of all of these things interacting and the internal perturbations between them. But it wasn't an important effect as far for electromagnetic theory and it was not an important effect about superconductivity, although a lot of people's attention was attracted and there was some good work that was done, that is, the electrodynamics of BCS was worked out as a result of this. But that stood its test of time when later on high-TC [High-temperature superconductors] came along and gave another push looking at these things. So I moved off into a totally different field.

BBV : Who told you that you had to work on another field ?

AH : Did you choose it yourself ?

BBV : How was the prevision of working on this field formulated ?

MD : Well, you start a job, and you discuss what you're going to do and they were very delighted to have me, to do pretty much anything I wanted. I was working in a Defense lab, you know Lincoln Lab was a Defense lab, and they had a whole bunch of different projects that they had to get done. But they had a few people like me that could do anything they wanted in sort of the basic research area, we don't have jobs like that, so it's hard to explain to somebody what I was doing. But when somebody needed some advice about some solid-state physics topic, that was working on some kind of Defense project, so they would come around and I'd tell them what I knew about it, that was sort of the way that part worked. So I had a lot of freedom, and so, I came around there, I saw what people were working on, and it was just so many exciting things going on. This was really the heyday of solid-state physics. I arrived there in June 1960, these were wonderful years in solid state physics. Lasers came along in 1960, and in fact, most of the people in the division, solid state division, went to work in lasers. But I didn't, I was one of the people that had so much freedom, that I didn't even have to do lasers like when everyone else had to do lasers, was sort of doing what they wanted, but was urged to go into lasers, but I didn't do that. So I started in this magneto-optics business because I thought that this was a really hot topic. And I was right. So I learned totally new technique, I didn't know anything about it, and so it was a lot of new things that I had to learn to do all those experiments.

AH : What's the new technique ?

MD : Well, optics, I had never done optics before, and it was magnetic field research. Well I've done magnetic fields, but that was little tiny fields that I worked with, that I was doing superconductivity work with ; 1000 Gauss was as high as we went. These are little solenoids was all I worked with, and I had a chance to work in that high-field facility. That was just, just beginning to come online. That was a very good research direction, I worked in that field until the Magnet Lab disappeared from MIT, mid-nineties. So I worked in that area for many years, not necessarily on magneto-optics, I worked on a lot of things with applied magnetic fields. So this career change that was imposed on me was wonderful, it was an exciting field. It's good when you're young to work in areas that are new, and maybe superconductivity was not as active at that point. Now when you turn around and look at high-TC superconductivity, we could have discovered it at that time, because I knew about this, and my almost next door neighbor was John Goodenough, who was working on just those materials that were involved in High-TC. Actually we talked to each other but we never worked on any project, because it wasn't, I wasn't supposed to be working with him. No, we didn't have an idea to try his materials, down at low temperatures with the superconductivity, no one had an idea like that.

BBV : How can you explain, because you tried a lot of materials, you were free...?

MD : No, I didn't try a lot of materials, I wasn't doing superconductivity. I made a switch to semiconductor physics basically at that point. So I was doing something different, and he was working with highly correlated materials. But not only studying magnetism, not studying superconductivity, that was.... But very very soon, after I learned of what they were doing I moved, I didn't want to work in the same areas that everybody was working on there was quite a large group, and most of them were doing very similar things. To me, the physics was not different, of course every material has a little different materials science, but there were no really new concepts, not much, it was working out a lot of details for each new material, which I could do. But I decided that I didn't want to do that, so that's how I started into graphite. My first work in graphite was maybe 1961 could have been the end of 1960, but 1961 for sure, and I've been there ever since, as you know. But I got the idea, there were several events - you know you never write about this exactly, so this is history of science - there were several events that happened in 1960 that made this all possible, and for some reason, I happen to know about some of this. In the UK, there was this discovery of how to make HOPG : Highly Oriented Pyrolytic Graphite. To do the experiments that I needed to do with the high magnetic fields we had to have samples that were a little bit bigger than the flakes of graphite that are normally found in nature. So the materials science of this project was worked out in the UK.

AH : What did they come out of ? Was there an industrial interest in this or what ?

MD : Well, different bases of carbon were interesting in 1960 because that's what I was going to mention to you, the year that diamond was artificially synthesized. So there was interest in the phase diagram of carbon diamond, and perhaps the work of Opaloda [?] in making HOPG was related to it.

AH : Do you know what the institutional setting was ?

MD : Yes, certainly, that was Imperial College in England, London, and I had occasion to visit him very very soon thereafter because there was a conference. The conference where the Josephson effect was announced, maybe, could have been that one, or could have been one before that. But I happened to be in the UK, and I dropped in at Imperial College and we met at that very early time, but when we met I already had quite a number of results. So we had something to talk about, because otherwise he wouldn't have been that interested in meeting a young person whom he didn't know anything about. So one thing was the material, and the second thing was there was kind of an interest in the field of carbon. Carbon became interesting when it was understood that were different faces... it wasn't only graphite which people had known well people knew diamonds but they didn't know how to go from one to the other, that wasn't really understood.

BBV : Were they trying to make carbon fibers over there ?

MD : The carbon fiber business came a little later, and my entry into it came later. If you want to go into that, I can, after. But maybe we should talk a little bit how the experiment started because that's never written up any place, so you might find some of that interesting. So all the different carbons that I tried because Raytheon was making carbons for, I don't know, military purposes, and the space program was already starting around that time and carbon was a lightweight material so there was quite a lot of interest. I tried some of their graphites but they didn't work, they just didn't have enough good crystalline quality. To do the experiments that I was after, an electron has to go through a whole cyclotron orbit before being scattered, that was the criteria. So if you have defects, impurities, whatever, that would interfere with that process. So I needed to have a high-quality crystalline material. Maybe a single crystal would be good but it wasn't big enough to get enough signal. I was looking for small defects.

AH : You're doing a magneto-...

MD : Optics, experiment. Well see ! I started out in the beginning doing my first couple of papers were magneto-optics and what other people were doing and that was kind of my learning experience ; and then I took a sidestep and I started another area which people considered too hard so we had virtually no competition because people considered the system too hard. It had a whole bunch of couple bands, four bands, and all people at that time only were thinking about two bands, valence and conduction bands. Anything beyond that was too complicated. So and the experiments could have been tough because it was a materials science problem and all that. But my materials science problem was solved by Opaloda, and there was a fellow at General Electric Laboratory that I found out about in 1960 and he was working in the US with this process of Opaloda. He followed the original work and he made me a sample and the first time we tried it it was beautiful So we were launched. So that might have been the beginning of 1961. We began to get a lot of spectra. Then we tried to figure out what it was that we were seeing. We now had a theory problem. Unfortunately, I don't remember exactly how this happened but when I was a graduate student at the University of Chicago, one of my colleagues, maybe two years older than me, but somebody I knew pretty well, was Joel McClure. He figures into this picture because somehow I made contact with him because he had moved into this graphite area, he wasn't doing that when he was a graduate student, but he became the person that developed the theory for the energy band structure of graphite. So we made contact and I remember him visiting me maybe the fall of 1962, before my third child was born. We were talking about how to deal with the band structure of graphite, explained all the spectrum, and I really got a lot of seminal ideas from him. My husband Gene understood immediately how to translate what he was doing to the experiments that I was doing. We developed a theory, and for our case adapted what McClure had done and extended it to explain the experiment and it worked very well. And so we were able, for the first time at that time to understand many of the details about the electronic structure of graphite. So that was 1962 or so, and I remember publishing a paper the first time this became kind of known on the outside was I was invited to an IBM conference, I don't know exactly the dates of that, but it must have been either late 1962 or early 1963. And that paper is published in the proceedings of the IBM journal. The IBM journal had a special issue for this particular conference and it was my paper on the Fermi surfaces of graphite. So that was one of the very early papers on Fermi surfaces of graphite, and we learned a lot of things. You know that it wasn't just ellipsoids that had more things associated with it and that was, we really did very detailed things with it. And actually what we did, that was interesting and new, and inspired by the work of McClure, but also kind of different as we had some kind of model that is still used today, basically. But it changed - I'll explain all the changes that happened because that's an interesting story for history of science maybe. So we have electrons in holes in graphite, and they were understood at that time and then I... (see every year, science moved slowly in those days relative to now, and I think we wrote a lot of papers on different aspects of this always getting better). Then some time in the mid-1960s, my very first graduate student, Sam Williamson and we did cyclotron resonance and van der Hofstad-Alfven effect, all of those things explaining about the Fermi surface. So we brought to bear all the different experimental techniques we could think of to look at this, and Sam Williamson went on to a very distinguished career. And he has a similar position to what I have at NYU, Institute Professor is my title here [at MIT]. He has similar position, but that was my first student. But his claim to fame isn't this, although his thesis I think was really very good. But he had an interesting career : he went to Rockwell International, got into semiconductor physics, like many of us did and superconductivity after that, and SQUIDS, magnetometers, came in at that time so he learned that technique and he had the idea just around 1970 of using that technique to look at the human brain. That's how he's known, a big name in brain science, using this technique. Yes, but related to what we were doing back, not so far off from what we were doing together in the late 60s. And with my second student after that we went (maybe he was my third student, but it was in very early times), we had the idea that if we took polarized light, doing the experiment in polarized light rather than circularly polarized light, we would be able to look at specific transitions, linear. Electrons go like this and they have different charge, the electron goes this way, the hole goes that way and they rotate in different ways, so we would be able to separate the transitions, and as soon as we did that everything fell apart because what we thought should have been electrons seemed to be holes, and what was holes seemed to be electrons. So this was pretty crazy ! Basically, the result of doing that polarized experiment, we found that everything that had been done on the electronic structure of graphite up until that point was reversed. That the electrons were holes and holes were electrons. Which was very sensible on the basis of fairly elementary considerations. That's why we thought that we were right. So when I submitted my first paper on this subject to the Physical Review, maybe it was Physical Review Letters, I don't remember exactly, but one of those journal articles, the reviewer was Joe McClure. And he was an obvious reviewer of this kind of paper, because he is a most knowledgeable person. And he revealed his identity ; they're not supposed to do that, but he revealed his identity. And he told me, "You don't want to publish this, people have been doing for the last twenty years all kinds of work with electrons this and holes that and how could you reverse it ? You must have something wrong with your experiment". So we checked and we checked and we checked and we said to him that "we think that we're right and if we're wrong, OK, we'll take our chances". And we went ahead and we published it. And as soon as it came out, the paper came out, we started getting letters and comments from different people. "So this is the explanation of this effect, and this is the explanation of that effect", and they had all these data in their drawers and they wouldn't publish them because they couldn't understand what was going on. A : The Emperor's New Clothes ! And then when we straightened out the electron/holes everything started fitting into place. And I had the real pleasure, so this is 1968 or so when we discovered that effect. In 1972, or maybe it was 1970, they had an international conference on low dimensional materials in Dallas, TX. And Joel McClure gave the invited talk on semimetals, or graphite semimetals, something like that. And he focused the entire talk on turning the electronic structure of graphite upside down bringing everybody's work, well we had done that also, but he did it on this occasion for everybody, and it was a very nice thing. And at that time, I gave the corresponding talk on the group V semimetals business because we had been working on that as well, in those early days, working out the electonic structure, the relation of all the group V semimetals. So that was kind of that early period when I was in magneto-optics. I was already at MIT because I joined the faculty in 1967. So 1968 when we turned the band structure of graphite upside down was my first year on the faculty.

AH : I wanted to ask you about the beginnings of the Interdisciplinary Laboratory at MIT. We actually talked to John Goodenough and I asked him if he had anything to do with it and he said "no, no, no, sitting out there at the Lincoln Lab, there was nothing", and it was almost a hostile atmosphere, they didn't want to have anything to do with him.

MD : Well, I was kind of a part of it. Let me give you a little background. You may have some difficulty but some of the people are still alive. The person who really started all of that was Arthur von Hippel. It's hard to interview him now ; you missed your window with him. He will have his 102nd birthday on the 19th of November [2001]. But he was a big factor in my early life ; he really liked all the things that we were doing. Now, when you're a young faculty member – a young female faculty member - it's maybe not so easy. But to have people who appreciate what you're doing makes things a lot better. So, he was always a good friend. Of course he escaped from the Nazis and all that. He came to the US. He came here, maybe '36 or '37, many years before me, and he started the Interdisciplinary Laboratory, which grew. They worked on many things, properties of dielectrics. See, we had this common background. That's a little bit how we met in the early times. They had ferroelectrics, piezoelectrics, they were growing crystals of all kinds, and phases of ice. There were a lot of books written. He was a big influence on the early solid-state physics. It's too bad because he was coherent until about five years ago, '97 or '96. He knew everything still. He was with it, but now he doesn't even recognize me. I think this is off-base, but there may be some people who know details about the lab. There's John Gelatis who is a microwave person and worked in this laboratory. He is still alive ; he must be in his 80s. He retired a long time ago. He wasn't really a PhD scientist, but he worked in the lab and might be a useful source. He may be able to tell you some other people who may still be alive. Most of the people that I can think of are no longer with us. There's George Pratt, who is faculty still, who came to MIT before I did and had quite a lot of contact with von Hippel, but I don't think he was a member of the lab per se. And he came after the 60s. In 1960, the Interdisciplinary Lab was formed, that I became Director of, but the origin of the lab goes back to the 1936 period and it evolved with von Hippel and he had different groups doing different things. It was his idea.

AH : Here at MIT ? The whole idea that materials science was all fields was his and he was ridiculed and took a lot of flak for that. But when the war came, the lab that he had and the people that he had were very much appreciated. That was the way to solve problems. So he got very heavily involved with war work. And he was anxious to be that because he had had such a bad time in Europe. A lot is written about this, I am sure the history books... You can find out a lot about it.

But you said that when the IDL was set up you were involved.

MD : Well, I wasn't involved. The idea was von Hippel's. I came and started working in the lab in 1960. I was working in the High-field [lab] which wasn't on campus. The High-field lab is not at Lincoln Lab. I was an employee of Lincoln Lab and maybe I analyzed some of my data, did some of the calculations, at the Lincoln Lab, but when I was actually doing the experiments I was here. And it was in the basement of Building 4. That basement of Building 4 is still there. I could show you exactly where that whole thing started. But von Hippel was in a different location : that was the Magnet lab. The Magnet Lab was really separate. The Magnet Lab had people doing all different things, so it was very interdisciplinary in the Magnet Lab. The Magnet Lab had, when I started, maybe a handful of people – we ran our own experiments. In 1962 or maybe 1963, Ben Lax who was my boss got the idea to start something called the national magnet facility and got the funding from the Airforce. They built the building in a bakery over in Albany Street and that became the Magnet lab but the pre-magnet lab, when I worked on it, was in Building 4. When we discovered the magneto-optics of graphite, that was done there, in Building 4.

AH : With all this interdisciplinarity, I presume you felt like a physicist. So, when the IDL was started with the name of Materials Science & Engineering, did you feel that this was a strange concept ?

MD : No. There were two reasons that I was very much at home in it. When I did my PhD-thesis I did it in an interdisciplinary environment. This will sound very strange to you but I got my degree at the University of Chicago. The laboratory where I had my equipment and where I was actually working was called the Institute of Metals. It had physics, chemistry, and metals. It was Cyril Smith, who was boss of the lab. He was the person I knew. It was totally funded by industry. Have you done any work on Cyril Smith ?

AH : No, but we have his books here in the basement – he bequeathed them to the Burndy Library.

BBV : Is he still alive ?

MD : No, no. He died in 1988 or something. He would be a lot older than me.

AH : He has left his papers to MIT.

MD : He had an impact on many things. His wife was an historian and the last 20-30 years of his life he did both history and science. He was a very interdisciplinary guy. He had been in industry and we had an id atmosphere. I didn't have much help doing my thesis but the people that helped me were from different people of all walks of life. I got people who knew how to do machining, vacuum systems, I got chemists. I used all these types of people that I felt comfortable with. So later at the Lincoln Lab we were also solving all kinds of things, and then you need all kinds of people. So I was very comfortable with talking to people, explaining physics principles to them. That was my function. I was brought to MIT as professor to teach physics to engineering students. I had a mentality already. The physicists here didn't want to teach physics to engineering students. They wanted the engineering students to come and take the physics courses exactly as they were doing it. They made no effort to have the physics have any relevance to what they were doing. This was the year of semiconductors and they weren't teaching the physics in any way related to that. When I came Gordon Brown was Dean of Engineering and he had the idea that the engineers missed out on WWII because they didn't know enough physics, and he wanted it changed by having people trained in physics teaching them, in addition to having experience with the engineering side, which I did. That's why I was attractive to them : because I had this dual background and didn't have a prejudice against engineers.

BBV : Did you adapt your physics course to engineers, and how ?

MD : Oh yes, ever since I have been here I have been teaching physics to engineers. I get physics students who come in also. Over the course of the years the physics department's students have moved towards what I was doing, because physics now has a lot of solid-state whereas when I arrived it had nearly none at all. Ben Lax, my boss, was a member of the physics department and he didn't get along very well with the others on the department, so that wasn't a great help in getting this... But he's still alive. You might want to interview him. And he is in order upstairs. He is still working in the lab.

AH : Well, we talked to Sam Schweber, who is also working with us on this project, and he has given me an account of the development of physics at Brandeis from theoretical physics asking philosophical questions towards a physics that can be used, towards engineering.

MD : They have focused a lot on theory at Brandeis, but the MIT experience was somewhat different, because it was favored a lot by WWII. The Radiation Lab, and also the materials group developed. There was a practical side also here. But it was not in the physics department. There was something in the Physics Department, but it wasn't very much. There was John Slater.

AH : Would you tell us something about your time as Director ; if it's not jumping too many years.

MD : Well that's 1977, so it's jumping a lot. I was the 3rd Director and when I took over the Lab was in big trouble ; it was about to lose its NSF funding. I had to keep the money coming in. That's what a Director has to do. The first Director was from Physics, the second was from Materials Science, and I was from Electrical Engineering. I did get a Chair in 1973 which gave me some independence and also some funds to do what I wanted. That's how the intercalation work started.

AH : Shall we drop the IDL and turn to the intercalation story ?

BBV : Yes please.

MD : My first contact in intercalation physics was Ted Gaballe.

AH : We have talked to Stan Whittingham, by the way, so we do have that perspective. I don't know whether that helps you.

MD : There was no contact between us for a long time so we both entered it very much independently I entered the field my first contact with intercalation physics came in 1965 or maybe 1964.

BBV : That early ?

MD : It's not written down, so you wouldn't know. But you could verify it. I got into it through a person called Ted Geballe he is a very well known person in this area. I strongly recommend that you talk to him. He is about 10 years older than I am. Because he really knows a huge amount of the early history. He was involved in many, many things in this field he is retired now but works pretty much every day in the lab. He discovered superconductivity in intercalation compounds when you add potassium in an alkaloid metal to graphite, it becomes an intercalation compound and he found that these materials were superconducting That's 1965 or 1964. I think it's referred to in my list [on the web].

AH : Yes, it is.

MD : Because it was a very important part of my thinking. He knew about my work on the electronic structure of graphite. We hadn't turned it around yet, it was still the old way. But he knew about our magneto-optics work and was sufficiently impressed with that and wanted me to do some kind of experiment that would illuminate what happened to the electronic structure after you made an intercalation compound out of it. Okay ? So that was what he wanted. And he invited me down to Bell Labs and we talked and I listened to what he had to say and I put it somewhere in the back of my mind. I didn't have an idea of what the experiment should be, so I didn't do anything and then in 1970 or 1971, there was a paper by a fellow called Moore (maybe something else) an Englishman, I think also from Imperial College He did the first experiment on the Hausser-Alfven effect in one of the intercalation compounds he showed that you could have cyclotron orbits long enough that you could get magnetic resonance data. When I saw that I knew that if I did an experiment that was similar with what he did with optics it would [?] We tried to make the samples and did the experiment, and I guess our first experiment would have been done about 1973. Because it took me a little while to find out about this paper I didn't see it the day it was published the reason that I mention this Chair is that doing this experiment was that I had this income that I could use for hare-brain experiments and things that maybe you couldn't get funding for. You always try to do an experiment first to make sure that it works before you send off the proposal, because if it's not going to work... I don't want to work there either so you do a little exploratory work - I think everybody does. It's certainly the way we do it. I used a little resources from my Chair to check it out and we got some interesting, encouraging results, so I said well, uh I'll put a student on it to solve it for a season and then of course we had to fund the student with research money so I tried to get money. In my career there have been very few proposals that have not been successful because I am really very modest. I don't ask for money unless I really need it and have a good idea I think that's the reason I have been successful in getting funding but that was one where I was not successful. The comments of the reviewers basically said, that a person with a physics background and my kind of background should not be mucking around with chemistry-related things that were so complicated that we would never understand. So there was a big potential barrier put up by funding agencies. I wasn't able to get anything. And those were the heydays when it was very easy to get money. Maybe I got a tiny little bit of money from the Materials Center, but they said : hush hush, don't tell anybody that you're doing this ! But I believe that as soon we began to get some more results and publications, I think I got my first grant in 77 so it was quite a few years when we were quite unable to get funding. What happened in 1977 was the first conference in intercalation ; the first big conference ever, in southern France, [Lanapour ?]. It's near Nice. Southern Riviera, very nice ! It was a very influential conference it was well attended and had an impact on almost everybody that went there. It revealed what was going on in intercalation physics and chemistry, it was mostly chemistry.

BBV : Who was the organizer ?

MD : Jack Fischer and somebody called Vogel whom you probably don't know he dropped out, he had a company he dropped out of the whole business five years after. He was an influential person in making it all happen maybe not so much for the science.

AH : I am sure Stan Whittingham was there ? You must have met him there ?

MD : Yes well, we could look back and find out. I believe he was there and there were people from all over the place that was the very first time that I met any of these people - total news for me.

AH : Because they were chemists ?

MD : No, almost everybody was new to the field. I'd been there much longer, but nobody knew I was there. Publishing in all these different journals there was no connection and listening to all the things they said ; then I knew what to do. You know, it had a big scientific impact and we came back to MIT and we started working in all the areas. I all of a sudden had a really good picture of what was going on in the field and then my students had a very hard time understanding what was going on in the field and I wrote an article now that article must have started about 1978 or very early 1979 ; I must have been Director of the Materials Center at the time, right ? Because 1977, when I went to Lanapour I must already have been Director because I am just figuring out the dates here - so anyway.

BBV : So you wrote this article.

MD : You know it takes a while to write these articles. Okay, so the article has a lot that should go like this, and it turned out that it should go like this is the way much of this did go. So that article is still referred to now, if somebody wants to look at the article on intercalation compound they often go to that ancient article that was written very early in the time of the field. Because of that, I was asked to do a similar thing for fullerenes, that's my big black book on fullerenes, and that came from Bell Labs researchers who felt that my pedagogic style was useful for researchers. And I guess they said, "I'm an old lady now, it's ok if I spend a few years studying everything that's been done in the field and digesting it and telling students what to do". But I'd done another one on carbon fibers, since you asked about carbon fibers, I did that one many years earlier.

BBV : So you suggest that this kind of review articles take a lot of time.

MD : They take a lot of time.

BBV : They are very useful to shape a discipline.

MD : Yes, and I had the opportunity to shape a few fields in this way. And the first one was the intercalation, you know at the time I was doing it, I of course had no idea that it was going to affect other people, I did it for my own students because they were working across such disparate areas and it was hard for them to figure out what it is that we were really doing. Because there's a lot of interdisciplinary research, and somebody's doing X-rays, someone's doing magnets, and another ones doing optics or infrared. Many many different things, and so they had to learn the field that they were doing, they learned the techniques and so forth, and they had to learn intercalation physics and see how it goes together and how it goes together with all the other guys. So having the review article helped a lot and it helped them in writing chapter one of their thesis too. So I found out how useful that was and that encouraged me to write more things like that later on. We were in intercalation physics until roughly 1990. I did a couple more things later on with with fast optics. We did some kind of elegant work.

BBV : And why did you stop ?

MD : Why did I stop ? Because I got into fullerenes and nanotubes, and their behavior too. It wasn't that ... I didn't have so many ideas, we'd done so many things already, the field had become mature as a result of other people who'd moved in, moved out. But I moved somewhere else and I, everybody's finite, you can't work on everything.

BBV : Do you have students who went, or are working on intercalation compounds because they need the technique ?

MD : No, not really, not really, let me explain about that. Maybe when you interview other people on the project, the ground rules are different. I'm at MIT and the expectation of the graduate student here is that they develop a new field, basically. So when I give a thesis topic, we develop some kind of thesis topic, every thesis I try to make like they're breaking some really new ground. There's a finite number of things that you could do. So maybe one thesis was on the structural properties of intercalation and we got into some interesting things with electron diffraction and we could do the surfaces. And then Raman processes. But after I finished all of those forays, big things, then I moved to something else. Okay ?

BBV : So you moved to fullerenes.

MD : Yeah, well I saw fullerenes as opening up totally new areas so and it's something I could understand in depth because it's only graphite that's rolled up in a scroll, I already knew about that. When I select topics, you know people always ask me, "How do you know what to work on ?" This is graduate students, so I say : you want to work on something new that people don't know much about, and so you take your chances, maybe it will develop into something, maybe it won't. But if it does, then you have a chance at doing something that's really quite new. Otherwise, you're just doing the same thing as somebody else did, and that's not really an MIT PhD. Being a thesis advisor here, I'm a little bit limited, sometimes I have some ideas, oh it'd be nice to do this and this, but that's just an extension of what somebody else did, and that's not appropriate for a PhD thesis. So you asked me about why I got out of intercalation physics. Well I didn't have ideas that were big enough and it's hard to find, when you get to the point where the field is mature, it's hard to find these kinds of good ideas.

BBV : And just one more question about intercalation compounds, did you have contacts with the French people in Nantes, Rouxel...?

MD : Oh yes, oh yes, I did. Yes. And in fact, still. I was with Rouxel two months before he died. We had an interview with the French TV, the two of us together I don't know, we had some kind of interview, it was in Nantes. They had a conference and somehow they sort of took me one day some place, and he was there, I was with him because he had ... Yes, the French, now I see why you're interested in intercalation physics, and chemistry in fact, is not sort of spread around the globe. There are few countries, the US was a player, for a while it was a big player, but only for a short time. France was working on it long before the US, we had one person here that was at Argonne National Lab who passed away, dear heart, I've just forgotten. But he was the big person, he was a giant in the field, but he was working in isolation. He passed away in 1965 approximately. He was originally from Europe, maybe came during World War II, or because of World War II, something like that. The French were very big, and the Germans were somewhat into it, but not as big as the French. And then the Japanese entered later and stayed longer. They're still there. And they were the ones that really started the battery business or aspects of the battery business in a big way. I think they had some of the very early patents on them.

BBV : Yes, on intercalation compounds. The French are not much interested in industrial applications.

MD : Well, yes, that's right, but the Japanese companies have pursued that. It was the first patent, I think in 1972 and well I remember that.

BBV : One question I would like to ask you because you give a lot of collaboration with the Japanese. Carbon fiber.

MD : Yes, oh you want to know that ? Well that happened because of intercalation. In 1980, there were some important collaborations in my career. The first one was not with carbon fibers, it was with Jean Paul [Lycee ?]. And that happened in 1970, we were in Dallas, TX, for this conference that I told you Joe McClure explained about the band structure of graphite and I was explaining about the group five semimetals. Well, they had the conference, it was a very small conference, and that evening, one of the evenings of the conference I went to a concert and I was on a bus going from the conference site to wherever the concert was. And on this bus was Jean Paul Lycee. And I had my badge and he had his badge. We were the only people on the bus with the badges. So I walked over and I introduced myself, I was older than him by a few years. It was okay to approach him I thought, and he of course knew who I was, but didn't know me. That was how we met, and then we started talking about our science. At that time he was working on bismuth, or antimony or something like that, and so I heard what he was doing, and I said, "Oh I know about that, and I know about that" and we started working together and we're still working. I just had something from him yesterday, so we're still working together.

BBV : You have been working together on different topics ?

MD : Oh, we worked on many many topics, we must have a hundred joint papers. But it started on that bus, going to the concert. And that was the beginning of, later on, twenty years later, of low dimensional thermal electricity that came from that meeting because I don't know if that would have happened otherwise. Because we had a dinner party and he invited somebody from France to meet me, and wanted to talk about the, the French navy wanted to know something about thermoelectrics, they had a guy from the ministry that came, and that conversation started the field, so, interesting thing, but I've written that out for the conference proceedings. Did I cover what you wanted on Endo ? Yes, let me tell you about Endo, because he started... 1970 was EC. We met at a conference. And 1980 I met Endo at another conference, and that was the second conference on intercalation physics. The first one was in France in [Lanapour ?], and the second one was in Provincetown, Massachusetts. And he came to that conference, and I was absolutely blown away by his talk on carbon fibers, it was nothing intercalation, well maybe he had intercalated by that time. But what I saw was that he could make these very long thin things and I said that those would be wonderful agents to do transport measurements. I just saw this vision when I heard his talk of all the things that we could do with those samples. And I didn't know that these things existed until that day. And I went up to him and I said, "I just loved your talk. Wonderful ! And we should do an experiment together", I said something like that, and we've been working ever since. So we have many papers too. Yes, but my collaboration with the Japanese is much older than Endo. Endo was not my first Japanese collaborator. But he's my first sort of applied. He's in applied areas, the other people that I worked with before are in more fundamental physics areas.

BBV : And when you have collaborated with Belgians and Japanese, would you say that you noticed different national styles in the field of intercalation ?

MD : Well, yes, there's national styles but there's personal styles too. Yes, not every Japanese is like every other Japanese and not every Frenchman… and Jean Paul Lycee is originally from Alexandria. He was born in Alexandria, Egypt, so I'm not sure he's exactly a typical Belgian either. So maybe he is, maybe he isn't.

BBV : It's much more personal ?

MD : Well, you know science is a universal language, so we can relate to everybody doing our science ; it breaks down all barriers. When I was doing something, I was president of AAAS and I was advocating with Madeline Albright the importance of the state department, this is the US state department, it should have scientific attaches at as many embassies as possible, because that was a ground where Americans at least would be respected and could talk to people. Rather than being hated and staking the battle on military operations. Think about things we could do together, we could, amount this crazy war on terrorism but maybe if we had a way to work with the populations that are disadvantaged, all the money that's spent on the bombs were spent on food, and improving people's living standards, maybe we would be much better off in the end.

BBV : So you still think that science wins peace among the people.

MD : Well it also brings war, all these tools for more destruction than ever before. So it's kind of a double, science has to be used in the right way too. Well I think we're all getting tired, and we have other things to do, maybe we could get together another time after you get a chance to look at what you have, and what you still need.

BBV : Yes, you can go and have a look on the site.

MD : Here ? Oh I used to be an advisor, I was on the board here in the institute for two full terms. I was here doing my thing until I started working for the US government, you know I was working for the Department of Energy. So I had to relinquish everything I was doing in the private sector.

AH : Why did you participate here [at the Dibner Institute] ? Why are you interested in history of science ?

MD : Well I was always interested in the History of Science and well I knew so many of these people, I was a student of Fermi, I just gave a talk for Fermi, on being a teacher and well so I gave the talk and I thought I had such interesting material it wasn't scholarly in the sense that I did a lot of research about Fermi but I just told stories that I knew. And I thought maybe someone would invite me to write an article on it because I thought it was, maybe, a little bit unique perspective, I just gave my talk, if people liked it, maybe they would record it, and that's it.

AH : So why don't you write it ?

MD : Well I don't have enough time. I always do things when I'm invited. You know how it is, we're pretty busy individuals. Well I have been interested in science and I've known just, you know when I started science was so small, everybody knew everybody. I'm talking about my student years, it was just handfuls of people. This wasn't like today, two orders or magnitude smaller. So many of the people that you're interested in, I knew them. Maybe most of them. In one way or another, our paths crossed. Even if we didn't write papers together, maybe we had some influence. But you know when I, I didn't realize it was Dibner, nobody tells me E56, they say Dibner Institute, I say, Oh okay I know that place. I've been here many times.

BBV : Do you think that you could help us to make contact with the Japanese materials scientists because we would like to have a case study of the US, and a case study on France.

MD : Are you willing to go over there ?

BBV : Yes we would go to interview people in Japan. For that we would need introductions. So if you could be kind enough to give us a number of names and contacts it would be really helpful for us, because it's very difficult, we cannot just come and say.

AH : Japan requires special entry.

MD : Okay, I'm very well known in Japan.

BBV : Especially in carbon fiber, because it is the topic we would like to investigate and you know everybody in the field.

MD : I do, well I don't, I wouldn't say I know everybody : I know a lot of people. I think that the book I wrote maybe was helpful. That book is out of print now, they want me to do a second edition. No time. But I'll do it, I'll do it. Carbon nanotubes are so exciting now that I'm- I don't have the time to write a book like the one I did the first time. It needs to go back in the literature for twenty years, I haven't been involved in everybody's doing, just what I'm interested in. Write a book it's a little different, you have to do the scholarly stuff. When nanotubes subside a little bit maybe it's a good time for me, basically if anybody's still interested. Well I'd be happy, what's your time scale ?

BBV : I'm leaving on Sunday but Arne is still here.

AH : To go to Japan, we were thinking the first half of 2002.

BBV : Sometime in there.

MD : Well, I'll get Endo, I'm going to see him in two week, I'm going to his lab he runs me ragged, he brings me to lecture in two different places in one day and that's my regular schedule there, it's kind of unbelievable because it's long distances and running around, very tiring, and you can't and every lecture is on a different subject of course.

BBV : But you can write on the train.

MD : (laughter)

AH : Well thank you very much !

BBV : It was really very rich for us.

MD : I'm not exactly sure what you're after so you'll have to sort of tell us a little bit.

Fin de l'enregistrement

Pour citer l'entretien :

« Entretien avec Mildred Dresselhaus », par Bernadette Bensaude-Vincent et Arne Hessenbruch, 25 octobre 2001, Sciences : histoire orale, /spip.php ?article82.

Pour citer l'entretien :

« Entretien avec Mildred Dresselhaus », par Bernadette Bensaude-Vincent et Arne Hessenbruch, 25 octobre 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article82.

Lieu : Dibner Institute, MIT, USA.

Support : enregistrement sur cassette.

Transcription : Bernadette Bensaude-Vincent, Helena Fu, Arne Hessenbruch.

Édition en ligne : Sophie Jourdin, Sacha Loeve.

GOODENOUGH John B., 2001-05

2010-02-04T14:39:22Z

John Goodenough, né en 1922 à Iena (Allemagne), est professeur et détient la Virginia H. Cockrell Centennial Chair in Engineering de l'University of Texas, Austin. Jeune homme, il s'est porté volontaire pour servir dans l'armée US comme météorologiste au cours de la Seconde Guerre mondiale. Après la guerre, il a étudié la physique à Northwestern University (près de Chicago) puis a travaillé au Lincoln Laboratory du MIT (Boston, Mass.) et dirigé l'Inorganic Chemistry Laboratory à Oxford University (Angleterre). Ses recherches portent sur les propriétés électroniques et ioniques des oxydes métalliques à la croisée de nombreux champs de recherche. Il a reçu le Von Hippel Award de la Material Research Society (MRS) en 1989 pour sa contribution à l'étude des solides où il s'est illustré par ses aptitudes à constamment lier les concepts de base de la physique et de la chimie à un large éventail de sujets théoriques. Goodenough est aussi reconnu comme l'un des scientifiques les plus influents des solid state ionics, champ de recherche sur les électrolytes solides.

BERNADETTE BENSAUDE-VINCENT (BBV) : So where did you start ? You graduated in chemistry, no ?

JOHN B. GOODENOUGH (JG) : No, not at all. Before World War II, I studied classics and mathematics. I took an introductory course in chemistry my freshman year at Yale as my science requirement for a Liberal Arts degree, but I had no thought of a career in science.

I had been awakened intellectually and spiritually while reading poetry at Groton School and trying to understand the metaphors of the Bible and the Church. Therefore, at Yale I was a young man in search of a calling for my life, so I read considerable philosophy. I became intrigued by the philosophy of science, and as I was reading Whitehead's Science and the Modern World, I came to the conclusion that, if I were ever to come back from the war and if I were to have the opportunity to go back to graduate school, I should study physics.

As an Army Air Force meteorologist, I dispatched tactical aircraft across the Atlantic Ocean during World War II. In 1946, while I was still stationed on the tiny island of Terceira in the Azores awaiting my turn to go home, a telegram arrived telling me to report back to Washington in 48 hours. In Washington, they sent me to Chicago where I was to have a choice to study physics or mathematics at either the University of Chicago or Northwestern University. My old Yale mathematics professor, Egbert Miles, had not forgotten me ! Confronted with this opportunity, I had a flashback to the evening I sat reading Whitehead before the military interruption. It seemed to me that "This is what I am supposed to do !" The next day I went to the University of Chicago to register for graduate studies in physics. When I arrived, the registration officer, Professor Simpson, said to me, " I don't understand you veterans. Don't you know that anyone who has ever done anything interesting in physics had already done it by the time he was your age ; and you want to begin ?"

BBV :It was really encouraging.

JG : Well, it didn't bother me at the time. I was simply grateful that, though still in the Army, my transition back to civilian life was so smooth. I left the Army in 1948 and continued my studies with the G. I. Bill of Rights. When I completed the 32-hour qualifying examination, I decided I did not want to go into nuclear physics, so I signed up to do my dissertation in solid-state physics with Professor Clarence Zener. When I finished my Ph.D. thesis, I had two job offers : one was to be an assistant professor at the University of Pennsylvania and the other was to join the Lincoln Laboratory of the Massachusetts Institute of Technology (MIT). I chose the latter.

ARNE HESSENBRUCH (AH) : What year was that ?

JG : That was 1952. Lincoln Laboratory had been established by the Air Force to develop the Semi-Automatic Ground Environment (SAGE) system for air defense. The system integrated radar, communications. and the digital computer. At that time the digital computer didn't have any memory other than a 16 x 16 bit electrostatic storage tube. Jay Forrester, an electrical engineer, had invented the coincident-current magnetic-core memory. This memory uses a magnetic torroid (core) with a square B-H hysteresis loop for each bit of stored information. Forrester had noted that the magnetic alloys Deltamax and Permalloy had the required square B-H hysteresis loops, and he had used them to prove the concept of his memory. However, the switching speeds were too slow. As an electrical engineer, he assumed the problem was eddy-current damping in his metallic cores, so he had ordered tape cores that were rolled to thicknesses as small as 1/8 mil. But the switching speed was still an order of magnitude too slow. Therefore, he had decided to investigate ferrimagnetic oxides that were insulators. My assignment was to help design a ferrimagnetic oxospinel that had a square B-H hysteresis loop. Those in Europe who had developed the ferrimagnetic spinels did not attempt to do this as they were convinced it was theoretically impossible. The problem was that you cannot role a brittle oxide as you can a metallic alloy in order to align the easy-magnetization axes of all the individual grains of a polycrystalline core, which is how the square B-H hysteresis loops are obtained in Deltamax and Permalloy.

The first thing I did was to analyze what controls the shape of a B-H hysteresis loop. I calculated where the domains of reverse magnetization are nucleated and what hinders their growth in a magnetic field. My calculations showed that if the crystallographic axes of easy magnetization are not well-aligned across a grain boundary, magnetic poles at the boundary may induce nucleation of reverse domains even where the applied magnetizing field is opposed to the magnetization in these domains. However, because the magnetization of a ferrimagnet is much smaller than that of a ferromagnet, nucleation of the reverse domains does not occur in a ferrospinel even where the easy-magnetization axes are misaligned until the magnetization is in the direction of the reverse-domain magnetization. This result meant that it was theoretically possible to obtain a square B-H hysteresis loop in a ferrimagnetic ceramic with unaligned grains provided some other defect could be introduced that would not only nucleate reverse domains at a desired reverse field, but would also release them, once nucleated, to grow until they reversed the magnetization. This was an important finding.

I also analyzed the factors that controlled the switching speed of a magnetic core. It was immediately apparent that the driving field to switch a core was restricted in the memory application to a magnetic field strength H = (H - Hc) < Hc where Hc is the threshold field to switch the magnetization direction. The coercive field Hc in the Permalloy tapes was too small to allow the driving force needed for fast switching. Moreover, the analysis showed that there is an intrinsic damping of spin rotations that would still be present in the absence of eddy currents. It was therefore clear that a somewhat larger coercive field Hc than that of Permalloy was needed, and the remaining problem was to discover the appropriate imperfection that should be introduced to provide many centers for nucleating domains of reverse magnetization at an acceptably large H » Hc.

Meanwhile, my colleagues were empirically mapping the MnO-MgO-Fe2O3 phase field to determine the compositional range of the ferrimagnetic spinels and the influence of annealing temperatures on the shape of the B-H hysteresis loop. It was in this phase field that promising hysteresis loops had been published. We found a certain compositional range rich in manganese in which the spinels were tetragonal rather than cubic. Previous workers had assumed that the tetragonal distortion was due to the disproportionation reaction 2 Mn(III) = Mn(II) + Mn(IV) since this reaction had been observed at the surface of Mn(III) oxides in acidic solution. However, I had read Pauling's The Nature of the Chemical Bond, which helped me to observe that the Mn(III) ion had an orbital degeneracy in a cubic octahedral site that would be removed by a distortion of the site to tetragonal symmetry. I therefore reasoned that at a critical Mn(III) concentration, there would be a cooperative orbital ordering that minimized the elastic energy and that the tetragonal distortion we observed was due to such a cooperative orbital ordering. Unknown to me at the time, Jahn and Teller had pointed out some years earlier that a molecule with an orbital degeneracy would distort so as to lower its energy, but my deduction was the first realization that, in a solid, cooperative orbital ordering to minimize the elastic energy would induce a crystallographic distortion below a transition temperature Tt. This effect is now known as a cooperative Jahn-Teller distortion. At higher temperatures and lower concentrations, the individual site distortions would be disordered and would fluctuate in what is known as a dynamic Jahn-Teller distortion. We also noted that we could obtain square B-H hysteresis loops in compositions that were cubic, but close to those that became tetragonal below a Tt, if the cores were annealed for a specific period at a precise temperature. In this way the technical problem was solved empirically ; the coincident-current magnetic memory proved to be a critical step in the development of the digital computer. However, I didn't know until some time later how the annealing procedure introduced defects that nucleated domains of reverse magnetization.

AH : When did you find this out ?

JG : The Russians were interested in our development of a computer memory. Therefore, I was invited to Sverdlovsk (now Katerinaberg) in 1961 to talk about our work. While there, Shur showed me evidence that the domains of reverse magnetization were nucleated within the grains and not at grain boundaries. In a 1964 experiment concerned with Li+-ion ordering on the octahedral sites of the spinel structure, I observed that the Li+ ions ordered with all trivalent counter cations except Mn(III). I then realized that annealing the memory cores for a specified period at a precise temperature was creating Mn(III)-rich chemical inhomogeneities within the cubic structure in order to reduce, through cooperativity, the elastic energy associated with dynamic Jahn-Teller fluctuations. These chemical inhomogeneities created magnetic poles within grains that were acting as the nucleation centers for reverse-magnetization domains in the memory cores.

BBV : So this is how you came to study oxides ?

JG : Yes. But let me tell you of one other deduction I made at that time that proved critical for my future studies. Néel had understood that the interactions between localized atomic moments may be antiferromagnetic as well as ferromagnetic. An open question at that time was the origin of the magnetic interactions and what determined their sign. Following a suggestion by Kramers, Phil Anderson had formulated the antiferromagnetic superexchange interaction in his Ph.D. thesis with Van Vleck. At the same time, neutron diffraction was developed as an experimental tool with which to measure directly the magnitudes of the atomic moments and their order below a long-range magnetic-ordering temperature. Wollan and Koehler had determined that the magnetic order in the antiferromagnetic perovskite LaMnO3 consisted of ferromagnetic (001) planes coupled antiparallel to one another along the c-axis (Figure 1 below). In La0.5Ca0.5MnO3, the magnetic order within the (001) planes consisted of both ferromagnetic and antiferromagnetic interactions. This anisotropic character of the sign of the (180o - f) Mn-O-Mn interactions in the pseudocubic MnO3 array was a mystery that delayed publication. I realized that the anisotropy must reflect a cooperative orbital ordering at the Mn(III) ions. As I had already worked out in my mind rules for the sign of the superexchange interactions that depended on the occupancies of the interacting orbitals, it was possible to predict the cooperative orbital ordering in LaMnO3 and the charge and orbital ordering in La0.5Ca0.5MnO3 so as to account for the magnetic order. We published back-to-back papers in the Physical Review. Kanamori subsequently provided a more mathematical formulation for the superexchange interactions, and the rules I formulated then are known as the Goodenough-Kanamori rules for the sign of a superexchange interaction. With these rules it has been possible to understand a variety of complex magnetic orderings in magnetic materials. Moreover, these studies led me to an investigation of the change from localized-electron configurations coupled by relatively weak interatomic superexchange interactions to itinerant electrons where the interatomic interactions become stronger than the intraatomic interactions. They also made me realize that, as a physicist, I could play a scientific role building a bridge between the engineer needing a material to realize a device and the chemist charged with the problem of designing a material that would perform the engineering function.

Figure 1. Perovskite structure

AH : And this realization came to you in the mid 1950's ?

JG : Yes, but its evolution was a bit more complex. When we had completed our project with the memory cores and working memories were being realized, Jay Forrester called us to his office. We expected to get a pat on the back, maybe a promotion. Although he spent 30 seconds congratulating us on a job well done, he had another purpose. "Now that you have worked yourselves out of a job, what are you planning to do ?" he asked.

AH : What an interesting managerial technique.

JG : Half the group decided to take the technology to industry ; I decided to stay and spent the next weekend figuring out what I should do next. I came up with the idea of a magnetic-film memory that would switch by a simultaneous rather than a sequential rotation of spins.

AH : Do you remember when that was ? Do you remember the year ?

JG : I believe it was 1956 or 1957.

BBV : So you stayed at the MIT Lincoln Laboratory for that ?

JG : Yes. I was put in charge of this new project as well as of the old ceramics laboratory. Since several people had left, I was permitted to hire a few new people. One of those I hired turned to me about a year later and said, "I want to become famous ; let me take charge of the magnetic-film project." He was an experimentalist, so I said, "All right, you can have it !" I gave my full attention to what was left of our ceramics laboratory. It turned out that the magnetic-film memory only filled a small niche in the market. It proved a difficult technology, and other developments came along that were more competitive. It appeared to be a good idea at the time, but it didn't become a winner. However, my decision to give the magnetic-film project to others made me concentrate on solid-state chemistry and gave me about 12 years in which I did some fundamental studies and wrote two books.

BBV : Which one : Metallic Oxides ?

JG : I wrote first Magnetism and the Chemical Bond. I realized I could tell a great deal about the nature of the chemical bond from the magnetic order and the crystallographic distortions because I knew how the signs of the interatomic exchange interactions depend on the number of electrons in the interacting orbitals and how cooperative orbital ordering would optimize the exchange interactions. In those days many people were interested in investigating the complex magnetic orderings revealed by neutron diffraction and in interpreting the origins of these complex orderings. For example, I was able in 1961 to show that where the Jahn-Teller distortions are fluctuating, the (180o-f) Mn(III)-O-Mn(III) interactions in a perovskite became isotropic, ferromagnetic vibronic superexchange interactions. Vibronic superexchange interactions are now returning as a subject of interest ; and we have recently shown they play an important role in the manganese oxides that exhibit a colossal magnetoresistance. Moreover, Tom Kaplan of my group was calculating the ground-state magnetic order where there were competitive interactions that gave rise to spiral-spin configurations, configurations that were quite complex in spinels where a spiral-spin configuration was superimposed on a Yaffet-Kittel triangular-spin configuration. I extrapolated the rules for the superexchange interactions to the case of itinerant-electron magnetism, reasoning that it was the perturbation expansion of the mathematical description and not the physics that broke down at the crossover from localized-electron to itinerant-electron magnetic interactions. In that book, my primary interest was in the variety of magnetic orderings that were observed in the d-block transition-metal alloys and compounds.

My book Les oxydes des métaux de transition is a French translation of a long review article entitled "Metallic Oxides". This review was an extension of my former book ; it concentrates on the transition from localized to itinerant electronic behavior. Localized-electron behavior occurs where the intraatomic interactions are stronger than the interatomic metal-metal or metal-anion-metal interactions, which is why the interatomic interactions between localized-electron configurations can be treated in second-order perturbation theory. The conventional one-electron band theory of itinerant electrons applies where the interatomic interactions are much stronger than the intraatomic electron-electron interactions. While I was still a graduate student, Mott had called attention to the fact that NiO should be a metal rather than an antiferromagnetic insulator according to the band theory. It is necessary to introduce into this theory the on-site electron-electron interactions to account for the localized-electron configuration of NiO. Hubbard presented the Hamiltonian that introduced this term, and the transition from antiferromagnetic insulator to Pauli paramagnetic metal where a band is half-filled is called the Mott-Hubbard transition. I realized that in oxides the metal-oxygen interactions open a large energy gap between the bonding and antibonding states of the valence s and p electrons ; d-electron redox energies may be found within this energy gap. Moreover, isostructural oxides were known of which some members were metallic and others were antiferromagnetic insulators. For example, TiO is a metal whereas MnO is an antiferromagnetic insulator ; SrVO3 is a metal whereas LaVO3 is an antiferromagnetic insulator. These observations meant that I should be able not only to determine the number of electrons in a d-electron bond from the sign of the spin-spin interaction across it but also to study the transition from localized to itinerant electronic behavior in d-block transition-metal oxides without the interference from overlapping broad bands that occurs in the magnetic alloys. However, our experiments designed to monitor this transition were frustrated at that time by lattice instabilities that gave rise to either phase separation or the appearance of a charge-density/spin-density wave (CSW/SDW). Before we could unravel why this was so, Senator Mansfield passed an amendment that forbade federally supported facilities like Lincoln Laboratory from engaging in fundamental research not targeted on a specific engineering application. So, I was told I could no longer continue my fundamental studies.

AH & BBV : When was this ?

JG : It was about 1970. So I had had about 12 years from 1958 to 1970 to do fundamental research.

AH : Was all of this done at Lincoln Laboratory ? Were you involved in the organization of the Department of Materials Science and Engineering at MIT ?

JG : Yes, the work was done at Lincoln Laboratory. No, I was not involved with the MIT-campus bid to establish an NSF-sponsored Materials Science Institute.

To return to my story, when I was told I couldn't continue untargeted fundamental research, I was forced to think through what I and my group should do next. It was the early 1970's, and the first energy crisis had arrived. People were lined up at the gas stations. So it seemed obvious that I should consider doing something related to energy.

AH : But there is a gap of more than a year because the energy crisis was in 1973.

JG : Yes, there was a gap during which time I developed a sole for a travelling-wave amplifier ; we made a MgO-Au composite that improved the secondary-electron emission by over a factor of 100. But the project manager who requested this development became preoccupied with a big radar sink for money, so the development was never exploited.

In the same period, researchers at the Ford Motor Co. had discovered fast Na+-ion conduction in a ceramic, sodium-beta-alumina. They proposed using it as the electrolyte and separator of a Na-S battery that used molten sodium as the anode and a molten sulfur compound as the cathode. It would operate at 300o C. I was asked by the DOE to be on the evaluation panel of this project. It was my introduction to solid alkali-ion electrolytes and to batteries. I was subsequently invited to Stanford University for two days to give a seminar on my work on the electronic properties of oxides with the perovskite structure and to interact with various solid-state research groups there. Each professor had his own fiefdom, and one of those was under Bob Huggins who asked me, "How would you design a Na+-ion electrolyte ?" Since perovskite-related materials were on my mind, I replied, "I would choose a host framework that contained tunnels as occurs in the hexagonal sodium-tungsten bronze, but I would choose structures in which the tunnels run in more than one direction and intersect one another. I would also choose a main-group element rather than a transition-metal atom as the framework cation to obtain a solid electrolyte, i.e. a framework that is not an electronic conductor." As I was flying back to Boston, it occurred to me that sodium-beta-alumina was a framework structure in which the mobile Na+ ions move in planes containing intersecting tunnels. I was interested to learn that, subsequent to my visit, Huggins and his post-doc Stan Whittingham used hexagonal tungsten bronze as a sodium-insertion electrolyte for measuring Na+-ion electrolytes. Meanwhile, I had decided to investigate Na+-ion conductivity in framework structures having tunnels running in three dimensions as I reasoned that a ceramic with three-dimensional Na+-ion conductivity would be superior to one with only two-dimensional Na+-ion conductivity. I embarked on this study before I turned to the problem of clean energy.

An analysis of the energy problem showed that there were only four alternatives to fossil fuels as energy sources : hydropower, geothermal, solar (including wind), and nuclear energy. Hydropower was already being exploited and geothermal energy is geographically limited. I didn't want to consider nuclear energy, so I analyzed the solar-energy problem.

AH : Why didn't you want to do nuclear ?

JG : I wasn't a nuclear scientist and we weren't a nuclear laboratory, so it wasn't appropriate for us. Similarly, wind energy was not matched to my interests. It would have been appropriate for us to work on photovoltaic cells, but others with more experience of broad-band semiconductors were doing photovoltaic development, so I began with wavelength-selective films for passive thermal heating. We developed some of these, but I soon realized that long-term energy storage was a key to harnessing solar energy. Since energy is most versatily stored long-term as chemical energy, I had the idea to generate hydrogen from water by photoelectrolysis. I soon discovered that Fujishima and Honda had already discovered this effect on TiO2 I also proposed the use of yttria stabilized zirconia for the electrolyte of a solid oxide fuel cell to be operated with the waste heat of a conventional power plant. As a third leg, I proposed continuing work on Na+-ion solid electrolytes for the Na-S battery. In that effort, I identified several framework structures (I called them skeleton structures) that supported three-dimensional, fast Na+-ion conductivity. One of these was Na1+3xZr2(P1-xSixO4)3, which has the hexagonal Fe2(SO4)3 framework. My colleagues named it NASICON, standing for NA SuperIonic CONductor, just as I was leaving Lincoln Laboratory.

AH & BBV : Who chose that name ? What was the name of your colleague who coined the word NASICON ?

JG : There were two I think : Alan Strauss and Kirby Dwight. When I requested funding to work on these energy products, the bureaucrats in Washington said, "The National Atomic Energy Laboratories are in trouble because atomic energy has gone out of favor. Therefore, the DOE will only support energy programs in these laboratories. Lincoln Laboratory is an Air Force laboratory and should involve itself with problems directly related to the Air Force." Therefore I decided that I should leave the MIT Lincoln Laboratory.

I had always wanted to help the third-world countries, and solar energy was a program that would be well suited to some of the countries newly enriched by the increase in oil prices. Therefore, when I was approached by an Iranian about the possibility of heading up a research institute in that country, I decided to explore the idea. I went to Tehran and raised $7 M from the Shah for an institute to be associated with the Aryamehr University there.

AH : When was this ?

JG : 1974 and 1975. While contemplating back in Boston whether to make such a move, a letter from Oxford University, England, arrived asking me to put my name in nomination for Professor and Head of the Inorganic Chemistry Laboratory. My wife did not hesitate to recommend that I put my name in nomination, and I thought, "If the people at Oxford have that much imagination, then perhaps that is what I should do." I was duly elected, and in 1976 I took up the post in Oxford.

BBV : So you abandoned your Iranian project ?

JG : I did.

BBV : And the $7 M ?

JG : Yes. As it turned out, within two years the Shah was ousted, the American Embassy was taken hostage, and the Institute I had helped establish was abandoned. My election as Professor and Head of the Inorganic Chemistry Laboratory at Oxford was quite extraordinary as I had had only one course in Qualitative Chemistry as a Yale freshman in 1940 and one in Organic Chemistry in 1948 at the University of Chicago. I came into Chemistry by the back door working with solid-state chemists trying to build a bridge between them and the engineer and using their expertise to design experiments to explore fundamental physics questions in solid-state science.

AH : Is that what the Oxford Inorganic Chemistry Laboratory was interested in ?

JG : The Oxford Inorganic Chemistry Laboratory included preparative organometallic chemistry, chemical crystallography, bioinorganic chemistry, thermodynamics, electrochemistry, and several spectroscopic groups as well as solid-state chemistry. My predecessor, Professor Stuart Anderson, was a solid-state chemist, and there was a preference to maintain continuity in that field. As I had been working with solid-state chemists, I presume the Dons thought I would bring a solid-state program that complemented other on-going activities there.

Initially, I decided to investigate the chemistry of the photoelectrolysis of water on oxide surfaces and to extend my studies of ionic transport in solids to include proton conduction in oxide-particle hydrates and insertion compounds for cathodes of rechargeable lithium batteries. These topics introduced me to electrochemistry as well as to catalysis, and I later undertook studies of methanol oxidation at the anode of a direct methanol-air fuel cell, of the oxygen-reduction reaction at fuel-cell cathodes, and the mechanistics of a partial-oxidation reaction on phosphopolymolybdates. The study having a large commercial impact was the development of a cathode for the lithium-ion rechargeable batteries that have enabled realization of the cellular telephone and laptop computers, for example.

In the early 1970's, Ted Geballe and his student Fred Gamble were investigating at Stanford the insertion of various chemical species between the layers of the metallic sulfide TiS2 in order to demonstrate the existence of two-dimensional superconductivity. Michel Armand, then a student with Bob Huggins, was interested in the possibility of reversible alkali-ion insertion in TiS2 for use as a battery electrode ; Stan Whittingham of Huggins' group had used hexagonal tungsten bronze, a one-dimensional Na+-ion conductor, as an electrode, and TiS2 offered two-dimensional conductivity. Brian Steele of Imperial College, London, suggested at a meeting (proceedings edited by Van Gool) the use of TiS2 as the cathode of a lithium battery. At that time, about 1973, the energy crisis had stimulated the EXXON corporation to expand into an energy company ; Stan Whittingham and Fred Gamble were hired to initiate an energy program. Before I left for Oxford in 1976, Stan Whittingham published a paper in Nature showing that lithium can be inserted rapidly and reversibly into TiS2 over the entire solid-solution range LixTiS2, 0 < x < 1, and that the compound gives a fairly flat open-circuit voltage versus a Lithium anode of about 2 V. This publication generated extensive interest, and EXXON committed considerable resources to the commercialization of a Li/LiClO4/TiS2 battery. However, a passivation layer at the anode resulted in lithium dendrite formation on recharge. After a few cycles, the dendrites grew across the explosive LiClO4 liquid electrolyte, shorting out the cell and blowing up the laboratory. Safety concerns eventually led EXXON to abandon the project and, subsequently, its expansion as an energy company.

As a consultant for the DOE on the Na/S battery, I had become increasingly aware of these developments. It became clear to me that to avoid these safety problems, it would be necessary to develop an anode that was an insertion compound. However, such an anode would lower the voltage of the cell. I considered the origin of the metallic conductivity of TiS2 and understood that it would be necessary to insert lithium into a metallic oxide if a larger cell voltage was to be obtained. However, unlike the sulfides, there are few layered oxides. On the other hand, there are several LiMO2 compounds having a transition-metal atom M that have layered structures analogous to that of LiTiS2, so I decided to investigate how many Li atoms can be removed before the oxide structure becomes unstable. Extraction of lithium meant operating on the M(IV)/M(III) redox couple. To obtain a large cell voltage, I wanted a cation for which the energy of the M(IV)/Mn(III) redox couple was unusually low ; and to prevent migration of M cations into the depleted lithium layer, I wanted both the M(IV) and M(III) species to have a strong octahedral-site preference since migration was through a tetrahedral site. Therefore, I chose chromium, cobalt, and nickel as possible M atoms. At that time, Koichi Mizushima was visiting me from the University of Tokyo, so I asked him to perform the experiments. We were delighted to find that we could take out most of the lithium from the cobalt and nickel oxides without migration of these cations to the depleted lithium layers. However, stable reversible lithium extraction is restricted to 50% - 60% extraction. Nevertheless, this amount gave a reasonable cell capacity at a voltage versus a Lithium anode of about 4 V.

At that time, all we had was a cathode material. The British battery makers were not interested ; they could not imagine beginning with a discharged cathode. A Japanese worker at Sony had been quietly investigating a special waste carbon as an anode host for the insertion of lithium in order to circumvent the safety problem of the battery, and he recognized immediately that my cathode was what was needed to make a high-energy-density rechargeable lithium battery. The Sony Corporation was looking for such a battery to enable marketing of the cellular telephone and the laptop computer. They have done an excellent job of commanding the market. It is my understanding that at the present time approximately 20% of the cobalt production in the world is used in these batteries. Already expensive, the price of cobalt threatens to go even higher. Therefore there continues to be a strong incentive to find less expensive alternatives.

With the publication of our results, Michael Thackeray was sent from South Africa to work with me. When he arrived, he said that he wanted to find a cheaper cathode and that he was inserting lithium into magnetite, Fe3O4. I was surprised because spinels were considered to be gem-like materials having little solubility of interstitial cations. However, I had heard Bruno Scrosati of Rome claim the same thing two weeks earlier, so I told Thackeray to repeat the experiment in my laboratory. This he did, and then I realized that the insertion of lithium was converting the spinel to a rock-salt structure. Both structures have a face-centered-cubic oxide-ion array. In the rock-salt structure, cations occupy all the octahedral sites of this array ; in spinels, only half of the octahedral sites are occupied to form a three-dimensional framework with an interconnected interstitial space of face-shared octahedral and tetrahedral sites. In the LiMO2 oxides, the M atoms occupy alternate (111) planes of octahedral sites. In the spinel, the remaining one cation to four oxide ions are ordered in tetrahedral sites of the interstitial space ; with two Li atoms for four oxygen atoms, the layered LiMO2 phase is more stable. Insertion of lithium into Fe3O4 was leaving the spinel framework intact ; the lithium entered octahedral sites of the interstitial space and pushed the tetrahedral-site iron into octahedral sites in a cascade. When I realized what was happening, I told Thackeray to insert lithium into the spinel Li[Mn2]O4 since I knew that in this spinel only Li+ ions would occupy the interstitial space and the [Mn2]O4 framework, though becoming metastable, would remain intact. This he did, and we found a flat open-circuit voltage versus a Lithium anode of 3 V. Removal of lithium gave 4 V. The possibility of an inexpensive cathode transporting Li+ ions in three dimensions stimulated extensive research on this cathode material even though the Li+ ions do not move as rapidly in this three-dimensional framework as they do in the layered oxides.

Unfortunately the manganese spinels do not retain their capacity on repeated cycling in the 4 V range. In the 3 V range, the flat open-circuit voltage reflects a two-phase range ; as the Mn(III) concentration increases with lithium insertion, a cooperative Jahn-Teller deformation from cubic to tetragonal symmetry occurs, and the deformation on repeated cycling tends to crack larger particles so as to cause capacity fade in the 3 V range as well. Recently, Sun Ho Kang came from South Korea to my laboratory in Texas, and we found that this latter problem can be solved by a simple ball-milling procedure that breaks the particles into many small microdomains. However, it looks like the manganese spinels will be restricted to the 3 V range and will face serious competition from other developments.

In order to increase the free interstitial volume for three-dimensional motion of the Li+ ions, I decided to reinvestigate the NASICON structure, but this time as an insertion electrode rather than as an electrolyte. The hexagonal M2(XO4)3 framework is found with several transition-metal atoms M and polyanions having X = Si, P, S, Mo(VI), or W(VI). For example, hexagonal Fe2(SO4)3 has the structure of the NASICON framework. Although the iron atoms are separated by (SO4)2- polyanions, the electronic transport is better than the Li+-ion transport. I was immediately struck by the observation that in this structure, the Fe(III)/Fe(II) redox couple gives 3.6 V versus lithium whereas the Fe2(MoO4)3 and Fe2(WO4)3 frameworks give 3.0 V. Changing the counter cation in the polyanion shifts the working redox energy just as shifting the Li+ ions from tetrahedral to octahedral sites in the [Mn2]O4 spinel framework changes the energy of the Mn(IV)/Mn(III) couple by 1 eV. Moreover, the more acidic polyanions bring the Fe(III)/Fe(II) redox couple into a useful energy range, thereby making an iron oxide a competitive electrode material. This fact was noted by Shigeto Okada of Nippon Telephone and Telegraph, and he was sent to my laboratory to work on stabilization of the hexagonal form of LixFe2(SO4)3. While he was with me, I asked my post doc, Kirakodu Nanjundaswamy, to investigate electrochemically the relative energies of several transition-metal redox couples in the NASICON structure with (SO4)2- and (PO4)3- polyanions. All the redox energies were found to shift by 0.8 eV on changing from (SO4)2- to (PO4)3-. At that time, my student Akshaya Padhi was looking for a thesis topic, so we decided to broaden the study by investigating lithium insertion into several different framework structures containing polyanions. In the course of that study, we found that all the lithium could be extracted from the olivine LiFePO4 and that it gave a constant open-circuit voltage versus Lithium of 3.4 V over most of the compositional range 0 < x < 1 of Li1-xFePO4 due to a small distortion of the FePO4 framework with x = 1. Professor Michel Armand of the University of Montreal recognized immediately that this material would be an excellent match to the polymer Li+-ion electrolyte that he had developed, so he persuaded the Hydro-Quebec Corp. to license our patent. He and Michel Gauthier of Hydro-Quebec then developed a fabrication procedure for achieving the full capacity on repeated charge-discharge cycles at a practical rate. This electrode material promises to be an inexpensive and environmentally friendly replacement for the present Li1-xCo1-yNiyO2 cathode, but other more competitive materials may yet be developed.

BBV : When did you come up with this new oxide ?

JG : In 1994.

BBV : So it is fairly recent. Were you still in Oxford ?

JG : No, I left Oxford in 1986. At that time, a generous donor had given to the University of Texas $8 M for Chairs in Science and Engineering provided the university could match it. In the end, $32 M was raised for a set of chairs, one of which was offered to me. From the endowment, they pay half my salary with enough left over to pay for a secretary and some expendables. Moreover, I didn't have to retire at 67, so I haven't yet ; I am an old tiger enjoying working here.

BBV :So you have a laboratory facility here ?

JG : Yes, we have managed to build up a nice laboratory in Texas. My battery work has been funded by the Robert A. Welch Foundation of Houston, TX. I am most grateful to that organization. They also supported the student with whom I developed the perovskites as solid oxide-ion electrolytes. Keqin Huang came from China to work with me on a solid oxide fuel cell (SOFC) based on the perovskite electrolyte Sr- and Mg-doped LaGaO3, first discovered by Ishihara of Japan. While still at Lincoln Laboratory, I had worked with a mechanical engineer to propose the SOFC as a bottoming cycle for a power plant ; our analysis was based as yttria-stabilized zirconia (YSZ) as the oxide-ion electrolyte. The DOE has since then provided Westinghouse with massive funding to develop the SOFC. Huang and I systematically developed a package of electrodes, buffer layers, and interconnects for a SOFC based on the gallate electrolyte, which we showed gave a competitive performance to SOFCs based on yttria-stabilized zirconia. Westinghouse has now hired Keqin Huang. It is not clear that the gallate electrolyte will be the winner, but the chemical lessons we learned in the process of building our cell will help in the selection of electrode materials and the use of buffer layers. I believe the SOFC technology, though difficult, will find commercial realization in the relatively near future.

But in 1986, while I was moving to Texas, Bednorz and Müller reported the discovery of high-temperature superconductivity in the copper oxides. This discovery brought me back to my study of the unusual physical properties that are encountered at the crossover form localized to itinerant electronic behavior in transition-metal oxides with perovskite-related structures, a study I had been forced to abandon in the early 1970's. Shortly after my arrival in Texas, a letter arrived from a physics professor at the Jilin University in northern China. He had a student interested in the high-pressure work we had done while I was at Lincoln Laboratory, and he wished to have him come to do a Ph.D. dissertation with me ; the degree was to be granted by the Jilin University. I arranged for the student, Jianshi Zhou, to come to the U. S. as a visiting scientist, and I put him to work on the copper-oxide superconductors. Fortunately for me, he continues at Texas in a most fruitful collaboration. We have used high pressure as a variable that allows not only the preparation of materials not accessible at ambient pressures, but also to monitor the change in electronic properties with increasing interatomic interactions in the region of crossover from localized to itinerant electronic behavior. High-temperature superconductivity in the copper oxides and a colossal magnetoresistance in the manganese oxides are found, for example, in mixed-valent systems at this crossover. I have invoked the Virial Theorem of mechanics to show that we can expect a first-order transition at the crossover with a (M-O) equilibrium bond length that is larger for localized than for itinerant electronic behavior. With this idea, we have demonstrated experimentally that where phase separation would occur at too low a temperature for atomic diffusion, it may be accomplished in perovskite-related structures by cooperative atomic displacements. Where these displacements are ordered and static, they give rise to the stabilization of charge-density/spin-density waves (CDW/SDWs). In a mixed-valent system, the cooperative oxide-ion displacements may remain only short-range ordered, in which case the electrons are strongly coupled to bond-length fluctuations that may either segregate a mobile, hole-rich phase or introduce vibronic particles consisting of hybridized electrons and oxygen vibrational modes. We have published a long review on this subject in volume 98 of Structure and Bonding that I edited. Our emphasis on bond-length fluctuations as the fundamental feature of the high-temperature copper-oxide superconductors has not yet been well-received by the physics community, which has concentrated on the importance of the interatomic spin-spin exchange interactions. Given correlation fluctuations that separate spin-rich and hole-rich regions, the spin-spin interactions clearly play a role, but they are associated with bond-length fluctuations that are a general phenomenon associated with the crossover from localized to itinerant electronic behavior. Unusual physical properties are found wherever the fluctuations are not ordered into a static CDW/SDW or do not give rise to a conventional phase separation as a result of atomic diffusion. However, short-range bond-length fluctuations are not detected directly by conventional diffraction techniques. Professor Takeshi Egami of the University of Pennsylvania has developed pair-distribution-function analysis of pulsed-neutron data that is providing a picture of the structure at time scales less than 10-13 seconds ; the data give direct confirmation of the existence of bond-length fluctuations.

AH : They model it on the computer ?

JG : The data analysis is done with the computer, but the pulsed-neutron data that are analyzed provide a picture of the lattice taken within a time that is short relative to a fluctuation. Egami is a careful experimentalist who was willing to develop a technique that could test our hypothesis directly ; his data are quite convincing, and I am very happy that he has been able to provide details of how these fluctuations order themselves into stripes, a detail that our indirect probes could not provide.

AH : So it's the matching of the neutron data with the simulation of the theory that is convincing because the two of them are similar.

JG : Not quite. There is no theoretical simulation of a model. Rather, there is an analysis of the data that provides a direct picture of the positions of the atoms in a short time interval rather than an average position obtained over a long time period. I believe their data on the copper oxides show that the bond-length fluctuations develop more and more long-range order on cooling to the critical temperature for the onset of superconductivity. I believe they order into a travelling CDW/SDW in which the electronic wavefunctions are hybridized with phonons to become heavy electrons, superconductive pairs condensing from the heavy electrons.

AH : So you don't go to many conferences either ?

JG : I go to a variety of conferences in electrochemistry, ceramics, materials science, solid-state chemistry, and physics. I limit myself to those where I am asked to give an invited or plenary lecture. This usually involves several invited talks a year, at least half of which are in Europe.

BBV : Over your career, you seem to have migrated from one discipline to another, finally coming back to where you started.

JG : I wouldn't say it was from one discipline to another, but from one inquiry to another and back again. But perhaps that's the way research goes, in spirals. I have found myself asking one question of a material at one stage and then returning to it to ask another question at a later stage. For example, when I applied the idea of cooperative orbital ordering to LaMnO3 and La0.5Ca0.5MnO3 to explain not only the structure but more fundamentally the anisotropic magnetic order with the formulation of the rules for the sign of the spin-spin superexchange interactions, Wollan and Koehler had also reported no magnetic order in the perovskite LaNiO3. I realized that the Ni(III) ion must have a low-spin configuration, but the lack of a cooperative orbital ordering as well as of magnetic order remained a mystery as everyone assumed the oxides are ionic compounds. At that time we were interested in how the mismatch of the equilibrium bond lengths of the two cations of a perovskite determined distortions of the structure from cubic symmetry or the stabilization of hexagonal polytypes. I went on to consider how the electronic properties would change as the strength of the interatomic spin-spin interactions increased. The metal-metal interactions across shared octahedral-site faces or edges seemed to be an obvious place to look for this change, and indeed TiO and VO are metallic whereas MnO is an antiferromagnetic insulator in which the Mn-O-Mn spin-spin interactions are stronger than the Mn-Mn interactions. When Morin discovered a semiconductor-metal transition in VO2 that is due to the onset of a CDW, I was prepared to think about it. Below the transition temperature Tt ? 67oC, the octahedral-site V(IV) sharing edges along the c-axis pair by forming V-V homopolar bonds. I realized that a change in the translational symmetry can transform a partially filled, narrow band of itinerant electrons into electrons of isolated molecular clusters. Professor Peierls had suggested such a possibility as a one-dimensional exercise in a physics textbook that I have not read, so the change from a one-dimensional narrow band to homopolar bonding between pairs of atoms of the chain is now known as a Peierls distortion. I further noted that MoO2, which is isostructural with VO2 at high temperatures, showed a similar Mo-Mo pairing at lower temperatures, but MoO2 remains metallic. The Mo(IV) ion has an additional d electron that occupies an orbital involved in Mo-O-Mo p bonding, so it dawned on me that covalent hybridization of metal-d and oxygen-p electrons could make the metal-oxygen-metal interactions strong enough to delocalize the electrons. This realization solved for me the mystery of LaNiO3. Paul Raccah had just joined my group from France and needed a project. I told him to prepare LaNiO3 ; he should find it is metallic ! Indeed, it is metallic. This was the first demonstration that the metal-oxygen orbital hybridization in an oxide could be strong enough to de-localize a d-electron configuration as a result of 180o M-O-M interactions. It solved the origin of the metallic conductivity of the sodium-tungsten bronzes, which had been puzzling since its discovery in about 1951. It also led me to map out where the electrons are localized and where they are itinerant in the single-valent oxides with perovskite structure as well as in oxides where metal-metal interactions de-localize the d electrons. At that time, I was unable to prepare the perovskite family LnNiO3, where Ln is a rare-earth atom, as these syntheses require a high oxygen pressure. Later, in Texas, J.-S. Zhou and I were able to show that LaNiO3 contains strong-correlation fluctuations within the band of itinerant electrons. As the size of the Ln3+ ion decreases, narrowing the s* band even further, these strong-correlation fluctuations order into a CDW/SDW below a transition temperature Tt that increases progressively with decreasing size of the Ln3+ ion. We were also able to show that the strong-correlation fluctuations introduce a progressive increase of a Curie-Weiss component in the paramagnetic susceptibility ; the character of the transition from Pauli to Curie-Weiss paramagnetism in the perovskites was addressed experimentally for the first time.

As another example, I had studied with Don Wickham the magnetism of the rock-salt system Ni1-xLixO, 0 £ x £ 0.5, and observed how the Li+ ions order into alternate (111) octahedral-site planes as x approaches x = 0.5. I was later to go back to this layered structure to demonstrate lithium extraction for the cathode of a lithium-ion battery.

I could cite other examples. Already in my first years at Lincoln Laboratory I understood the need to build bridges between physics, chemistry, and engineering in order to be able to design materials that would perform a desired engineering function as well as to explore the fundamental questions of solid-state science. This interdisciplinarity is the hallmark of materials science.

BBV : Do you think of yourself as a physicist, or a solid-state chemist or...

JG : I am a solid-state scientist.

AH : Don't you identify with any of the established categories ?

JG : Well, I would like the chemists to think I am a chemist, but I'm afraid they think I am a physicist. On the other hand, the physicists think I am a chemist.

BBV : That's like the story about Einstein who is a Jew in Germany, but he was a German in Switzerland.

JG : Well, that's life.

BBV : Yes, it's life. But you have been publishing in several journals.

JG : Yes, of course. I am a Fellow of the American Physical Society, and I publish a great deal in the Physical Review and Physical Review Letters. I also was elected as a Chemist to be a Foreign Associate of L'Institut de l'Academie des Sciences de France as I have published extensively in the Journal of Solid-State Chemistry, in the Journal of Electrochemical Society, and in other chemistry journals. I was elected a Fellow of the National Academy of Engineering because I publish in materials science journals such as the Materials Research Bulletin. Thus I identify with all three established categories and am an Associate Editor of several journals.

BBV : I understand you have strong links with the solid-state chemistry community.

JG : Yes, I do. I believe the solid-state chemistry community has been the most appreciative of my attempts to build a bridge between the chemist and the physicist. I have used the experimental strategies of the chemist to explore problems of interest to the solid-state physicist.

BBV : So finally the physicists are accepting you ?

JG : Yes, but sometimes I think a bit reluctantly by some.

AH : And you also publish in Nature.

JG : Yes, I publish in Nature.

BBV : Have you had any links with the people in Grenoble ?

JG : Yes, but no collaborative links aside from a few with workers using their neutron-diffraction facilities. My ties to Grenoble go back to 1954 when I paid a visit to L. Néel, R. Pauthenet, and E. F. Bertaut long before they built up the great facilities there. In 1954, I was able to take a one month leave of absence in addition to my annual vacation, and my wife and I made a splendid tour of Europe. Since I had been working on spinels, I decided to take a side trip from Switzerland to Grenoble to pay my respects to Louis Néel who received a Nobel Prize for his work on ferrimagnetism in these oxides. I also wished to see Erwin Bertaut who had done much pioneering x-ray diffraction on the spinels, perovskites, and garnets ; Pauthenet made the magnetic measurements. I brought to Bertaut my deduction of cooperative orbital ordering in the manganese and copper spinels, and he was delighted to have an explanation of his observations. From that time I have felt a special friendship for Bertaut and for Pauthenet before his too early death. Louis Néel was kind enough to invite me to give a paper at the next International Conference on Magnetism that was held in Grenoble. When I was in England, I went each Spring to Grenoble to referee applications for neutron-diffraction studies there. I have also been invited for 10-day stints to lecture at the University of Grenoble and at the CNRS Crystallography Laboratory that was founded by Bertaut.

BBV : And what are your relations with Professor Paul Hagenmuller ? He is in exactly the same field as you.

JG : My relations with Paul Hagenmuller also go back a long way. The CNRS decided to diversify from Paris some important scientific centers. Grenoble was the first ; Néel, Bertaut, and Pauthenet built up that facility. In the early 1960s Hagenmuller was chosen to develop a solid-state chemistry group in the University of Bordeaux. Already in the early 1960's, before his building was completed, Hagenmuller came to visit me in Lincoln Laboratory. I strongly advised him to build contacts with the physics community. He has had a little difficulty bringing a physics component into his laboratory, but he did develop techniques for physical measurements and his people have interacted with physicists in Paris and Grenoble. In the late 1960s I was able to accept an invitation from him to spend three months in his laboratory ; it was on that occasion that André Cassalot translated my "Metallic Oxides" into the French book Les oxydes des métaux de transition. I have visited, lectured, and collaborated with his people over the years ; and in 1976, Hagenmuller offered me a post in Bordeaux that I declined in favor of the position at Oxford. I received a Docteur honoris causa from the University of Bordeaux in 1967, and I have served as a CNRS advisor to his laboratory as well as to the Bellevue laboratory of Guillaud in Paris. I have had numerous enjoyable contacts with colleagues in France, including an early invitation from Jacques Friedel to spend a year with him in Paris and acting as examiner for many a Thése d'État at several universities. I have had less interaction with Germany.

AH : Why is that ?

JG : I believe it is just a coincidence. Right after World War II, Germany emphasized the rebuilding of their industrial base. Although there was a strong solid-state chemistry tradition in Germany, the chemists like Rabenau and Hoppe were isolated in different universities and were primarily preparative and structural chemists. The Max Planck Institutes did not establish solid-state centers until relatively recently, and they have been slow to recognize the need for interdisciplinarity. However, I have had a little contact with Arndt Simon and Manuel Cardona of the Max Planck Institute in Stuttgart, but there is relatively little overlap between their work and mine. I served with Manuel Cardona as an advisor to the Spanish CSIRO for several years. I also served as an advisor to the Materials Science Center in the University of Groningen when it was first being established under George Sawatzky on the retirement of Franz Jellinek and Cornelius Haas there. I have been better received in Europe than in the U. S.

BBV : But the solid-state community is small here.

JG : Yes, the solid-state chemistry community is only now becoming prominent in America. When I came to Lincoln Laboratory in 1952, the chemistry departments in this country considered that solid-state chemistry was only an exercise in stamp collecting as the community consisted largely of structural chemists. It was only in a few industrial interdisciplinary laboratories like the Bell Telephone Laboratories and IBM that the solid-state chemists were interacting with engineers and physicists. However, even there they served the physicists and engineers by providing them with single crystals. When I took charge of the small ceramics facility at Lincoln Laboratory, I said to myself that I wanted to make the physicist serve the chemist rather than the other way around, so I said to my people, "We have got to be the dog, not the tail ; we will let the physicists be the tail, not the other way around." I suppose it was that attitude that made Oxford accept me as a chemist.

AH : It seems that you have had quite a lot of contact with the Chinese and Japanese.

JG : I see you have done a lot of homework.

AH : We can see Chinese and Japanese names on your publications in the last five years.

JG : You should also see several Indian names. In my years in Texas I have had post doctoral and doctoral students from China and India as well as visiting scientists from Korea and Japan. I have already told you about J.-S. Zhou and Keqin Huang. My contacts with Japan also go back a long way. My first trip to Japan was in 1961. I had been invited there the year before by Nagamiya, but I could not go then. Junjiro Kanamori was his student, and he went to work with Jacques Friedel when I couldn't get leave to spend a year in Paris. Nagamiya and Kanamori were interested in my rules for the sign of the superexchange interactions and my prediction of cooperative orbital ordering in LaMnO3. There were other Japanese working on ferrites who came to visit me before 1961. One was Shuichi Iida of the University of Tokyo. It was his assistant, Koichi Mizushima, who came to me in Oxford and did the initial experiments on the Li1-xCoO2 and Li1-xNiO2 battery cathodes.

During my visit to Japan in 1961, Pauthenet of Grenoble and I were invited by Eiji Hirahara to lecture in Sendai ; I exchanged Christmas greetings with Hirahara every year until his death and interacted with him on the MnP-MnAs system. On that occasion I was also invited to lecture in Sapporo where I remember the pleasure of eating corn on the cob sold by a street vendor. In 1976, I was invited by H. Watanabe of Sendai to be a three-month visiting scholar of the Japanese Academy of Science, but I was only able to stay one month because I had to take up my new post in Oxford that autumn. I have had quite a few invitations to visit Japan, and I have enjoyed interacting with the scientists there. The Japanese have made a wonderful contribution to my fields of interest, and I have been a member of the Japanese Physical Society since about 1954.

The Japanese were interested in my work on magnetism in the early days and our work overlapped quite a bit. For example, Chikazumi was interested in my analysis of the factors that determine the shape of a B-H hysteresis loop, our discovery of cross-tie domain walls in thin films, and the damping factors that control the speed of domain-wall switching during a magnetization reversal ; he was in the process of writing a magnetism text book. Tom Kaplan, who was working with me in the late 1950's and early 1960's, discovered theoretically the possibility of spiral-spin configurations as a result of competitive exchange interactions ; the same theoretical discovery was made simultaneously in Japan and France, each from an analysis of the magnetic order in a different compound. We had a hard time convincing the theorists that the period of a spiral-spin configuration need not be commensurate with the crystal lattice. Tom Kaplan was interested in calculating the ground-state configuration ; as an experimentalist E. F. Bertaut of Grenoble was interested in deciphering the complex spin configurations revealed by his neutron-diffraction experiments. Both independently came up with the same mathematical formalism. There are moments when the time is ripe for certain ideas to emerge, and people working in different countries come up with similar solutions at the same time. Who gets the credit is important for the individual scientist, but it doesn't really matter for the progress of science.

More recently, the Japanese have been actively studying high-temperature superconductivity in the copper oxides and the colossal magnetoresistance in the manganese oxides. Professor Tokura has a large group growing single crystals, and we have made measurements on a few of his crystals. Mikio Takano, now a professor at the University of Kyoto, collaborated with me on the demonstration of a pressure-induced high-spin to low-spin transition at the Fe(IV) ions of CaFeO3.

AH : So the Japanese with whom you had contact were all in the university world ; it wasn't SONY or another corporation ?

JG : They were, for the most part, all in the university world or a research institute. But of course, SONY commercialized my work on cathodes for a rechargeable lithium-ion battery ; it was the basis of my selection as a Laureate of the 2001 Japan Prize. Because of this work, the Nippon Telephone and Telegraph Company sent Shigeto Okada to me and SONY sent me Yamada for a year.

AH : You allowed them to do that ?

JG : I have always been happy to receive good people who are funded by a home laboratory to which they will return. I don't have many sources of funding. David Nelson at the National Science Foundation has provided support for a post doc and a student and the Robert A. Welch Foundation has provided support for two students. I have had a little miscellaneous money from time to time that has helped me get through some lean times.

BBV : Does it cover equipment as well as students ?

JG : Not permanent equipment, but expendables.

BBV : You said you were interested in developing materials that would perform an engineering function. Do you go after research for industrial development ?

JG : No, I don't do industrial development ; but I do long-range targeted research. For example, when we developed LiFePO4 as a cathode material, we patented it and licensed it to the Hydro-Quebec Corporation. The people in Canada did the industrial development of how to fabricate a commercially viable material. Once I have identified a material that will perform a desired engineering function, I leave it to industry to commercialize it.

BBV : But if you have a problem-solving approach rather than an end-product approach, then the problem that you solve might be used for several end products rather than one. Which approach would you recommend for research productivity ?

JG : Research is productive not only when it produces a commercially viable end product, but also when it increases our understanding. Let me make a distinction between long-term targeted research and fundamental research that uncovers new phenomena or provides the understanding needed to know how to go about designing or searching for a new material for a specific engineering function. Examples of my targeted research efforts are the development of the ferrite memory core, of solid electrolytes, of battery cathodes, of materials for a solid oxide fuel cell, of wavelength-selective films for heating with solar energy, of a sole material for an amplifier tube that emits nearly 100 secondary electrons for every primary electron that strikes it, or our unsuccessful attempt to photo-electrolyze water with sunlight in one step rather than two. Yes, in the process of solving or evaluating these long-range targeted-research problems, we did more than obtain an end product ; we also learned a great deal about materials that not only increased our fundamental understanding, but also was to prove useful for solving another targeted-research problem. For example, our demonstration that a thin buffer layer can be used to prevent a chemical reaction between the electrolyte and the anode of a solid oxide fuel cell immediately suggests fabrication of a bilayer oxygen-permeable membrane for partial oxidation reactions. However, targeted research needs to be driven by a well-defined engineering need and a careful description of the engineering constraints expressed as a material "figure of merit" or some other set of criteria. If the engineer does not have a material in hand that can do his job, he can only turn to long-term targeted research to indicate the feasibility of the problem if not a solution to it. In my view, long-term targeted research is well served when there is a balance of fundamental research that can bring the discoveries needed to resurrect abandoned projects or to inspire new engineering concepts. I try to maintain such a balance in my research group. It would be unfair to ask a student to do a Ph.D. thesis involving an end product that is already under intensive development by industry.

I would also distinguish between the extrinsic and intrinsic properties of materials. For the most part, I have been interested in the intrinsic properties of a material whereas the industrial scientist is often concerned with how to optimize performance by changing its extrinsic properties such as shape, morphology, single-crystal versus polycrystal, or doping level. However, we did stabilize the capacity of the manganese-spinel cathodes by ball milling to create microdomains in our particles. Nevertheless, I am not a typical material scientist concerned with problems of fabrication and manufacture of materials that have already been identified as suitable for a particular end use. That's why I consider myself a solid-state scientist more than a materials scientist.

AH : But isn't the market the ultimate driver ?

JG : Engineering problems are driven by the market. But as a scientist, curiosity is also a driver ; one wants to understand the physical processes that govern the material properties we observe and exploit. Solving a problem in materials engineering may require addressing fundamental scientific questions. These are the problems that I prefer. For example, the market would like an electric car that performs as well as the cars we drive today. An engineering solution would be a direct methanol-air fuel cell. It would make possible an electric car powered by a liquid fuel just as the present-day internal-combustion engine is powered by gasoline. Conversion of the chemical energy in methanol to electric power in an electrochemical cell is a well-defined engineering problem, and the engineering constraints are defined by the performance of today's automobiles. However, to achieve adequate power requires identification of a solid H+-ion electrolyte and probably a better methanol-oxidation catalyst as well. Identification of materials that can perform these functions requires understanding of the processes that govern the phenomena of interest. Until these materials problems are solved, there is no point in proceeding with the engineering.

BBV : It seems to me that when you addressed the problem of an electric car in a 1978 paper, you didn't separate the electrolyte and electrode problems. You appeared to address both problems without separating them.

JG : The electrode and electrolyte problems are clearly separable ; each performs a different function. The anode must be an electronic conductor that catalyzes the oxidation of methanol, CH3OH, to carbon dioxide, CO2, and H+ ions whereas the electrolyte must be an electronic insulator that conducts protons. The cathode must be an electronic conductor that reduces the dioxygen molecule O2 to two oxide ions that combine with the H+ ions coming from the anode on the other side of the electrolyte. Carbon dioxide is the exhaust product at the anode, pure water is the exhaust product at the cathode. The entire package of electrodes and electrolyte must be considered together because the chemical potentials of the electrodes must be matched to the stability window of the electrolyte. With an H+-ion electrolyte, the cathode must be porous to allow escape of the water produced at the electrode-electrolyte interface. In a solid oxide fuel cell, an oxide-ion electrolyte allows use of a mixed oxide-ion/electronic conductor since there is no exhaust product emanating from the cathode/electrolyte interface in this case. Nevertheless, the chemical potentials of the electrodes must still lie within the stability window of the electrolyte.

BBV : Do you think you have contributed more to electrodes or to electrolytes ?

JG : I have contributed to both, but more to electrodes. My contribution to the lithium-ion battery has been the cathode, for example. I have made no contribution to either the liquid or the polymer electrolytes used in these rechargeable batteries. I have pioneered the use of a perovskite for the solid O2—ion electrolyte of a solid oxide fuel cell, but my more fundamental contribution was my early work on metallic perovskites that led the way to the use of these oxides as cathodes of the solid oxide fuel cell ; they include the purely metallic manganese oxides and the mixed oxide-ion/electronic conductors. All of the early fundamental work on metallic perovskites and my later work on perovskite oxide-ion electrolytes have provided a basis for selecting cathode and electrolyte materials, but the perovskite electrolyte faces stiff competition from oxides with the fluorite structure.

BBV : And what is your opinion about a specialized journal for the community of researchers working on solid-state ionics ?

JG : I have not been a strong advocate of specialized journals. On the other hand, solid-state ionics has become an important sub-field of electrochemistry, and I can understand the need for rapid publication of developmental results in a specialized journal. I would expect the more fundamental studies to be published in non-specialized journals. On the other hand, Physical Review and the Journal of the American Chemical Society cover so much territory that there was a need to create a Journal of Solid-state Chemistry. This journal has been quite successful, but I worry a bit that its emphasis may become too much on the preparation of new compounds and their structural characterization as new specialized journals are beginning to pull away papers on targeted research and the physics journals pull away the papers having a strong physics component such as those on high-temperature superconductivity and the colossal magnetoresistance.

When I went to Hawaii to receive the Olin Palladium Medal from The Electrochemical Society, I was struck by the tremendous impact of solid-state ionics on that society and on solid-state chemistry. The fact that people are making a great deal of money with the lithium-ion batteries and that the fuel cells are showing more commercial promise has brought financial support into the field. I expect the LiFePO4 cathode will stimulate the field further. It is cheap and environmentally benign, so it may become competitive in large batteries. I can't claim to have designed it ; but I did have an idea where to go fishing. In any case, the field of solid-state ionics is growing, and journals that cater to the field will undoubtedly prosper.

BBV : One more factual question. You have had a lot of students over the years. Did you teach ? Did you have to teach ? What difficulties did you have with teaching ?

JG : Lincoln Laboratory was a Research & Development facility separate from the MIT campus. During my 24 years there, I had only one Masters and two Ph.D. students and I only gave a short series of lectures, never a formal course.

The system at Oxford is totally different from that of a U. S. university. Students come up to Oxford to read Chemistry with two years of Advanced Level science courses that are equivalent roughly to the first two years in a U. S. college. Chemistry students were selected by each College by the Dons of that College who coached them for three years for a career-making final examination. The Inorganic Chemistry Laboratory provided a mandatory Practical Course and a series of 8-lecture courses that were optional, but generally provided material essential for the big final examination. I gave lectures on solid-state topics that were not necessarily covered in their finals, so the half-life of the attendance in my classes tended to be fairly short. After the final, the students did a fourth year of research for their undergraduate degree. My principal contribution to undergraduate teaching was probably the supervision I gave to those who chose to do this research year with me.

At Texas I am required to teach two graduate courses a year. I have also taught undergraduate courses in Mechanical Engineering and Electrical Engineering. I prefer teaching the graduate courses. Of course, my hope is that considerable learning occurs in the course of completing a Ph.D. with me. Those who have absorbed the most are a few excellent students and the better post docs.

AH : I would like to run with the instrument ball for a bit. How do you see the development of instrumentation having an impact on your work ?

JG : That 's a big question.

AH : Maybe you could start by saying what was available in 1951 when you started.

JG : Let me restrict myself to the field of transition-metal oxides. In 1951, ceramic materials were made mostly with high-temperature powder-metallurgy techniques or hydrothermal synthesis. The use of organometallic precursors to lower firing temperatures was a novel idea. Physicists wanted single crystals. The growth of single-crystal magnetite was a major undertaking and achievement. Zone refining of germanium to achieve single crystals of high purity was being developed ; oxide crystals were grown primarily by the Czochralski technique of pulling a seed crystal from the melt. Crystal growth from a flux was just being developed as an art. Now we have an image furnace with which we are able to grow oxygen-stoichiometric oxide crystals of high purity. In 1951, chemical characterization rarely included the analysis of oxygen stoichiometry ; thermal-analysis instruments were not commercially available, and mass spectrometers were used. High-pressure synthesis was carried out in a few laboratories, but techniques for applying high oxygen pressures were not yet developed. Thin films were prepared by primitive sputtering machines. Since those days, soft chemistry is widely used for synthesis and more complete chemical characterization of ceramic materials has become normative. Films are now deposited by a variety of techniques, many of which were not then available. Laser deposition is an example.

In 1951, the electron microscope did not have the high resolution that is available today. The first direct observation of a dislocation was made at that time. The principal tool for structure determination was X-ray diffraction, but analysis of the data was laborious. The first observation of antiferromagnetic order by neutron diffraction was made at that time. Neutron-diffraction and scattering measurements have now become sophisticated and fundamental tools in solid-state science. The advent of synchrotron radiation and pulsed neutron techniques have enabled direct observation of structure at short time scales, which is opening a whole new field of study.

Various spectroscopies were available in 1951, but photoelectron spectroscopy had not yet been developed and nuclear magnetic resonance was in its infancy. Mössbauer spectroscopy and the laser had not yet been imagined. A principal tool at that time was electron paramagnetic resonance. Impedance spectroscopy for measuring the ionic conductivity of electrolytes was not commercially available.

The superconducting magnet and the SQUID magnetometer did not exist. To obtain a magnetizing field of 50 kOe was a big-science project. The vibrating-sample magnetometer was developed at Lincoln Laboratory by Simon Foner in the late 1950s, and Don Smith of my group developed a vibrating-coil magnetometer that allowed us to do magnetic measurements under high pressure. However, the measurement of physical properties under high pressure is still restricted to a few laboratories.

The development of affordable, powerful computers for data collection and analysis has transformed the accuracy and speed with which measurements can be taken. It has quite revolutionized the experimental laboratory.

AH : So what was the infrastructure of the Lincoln Laboratory, of Oxford, and here in Texas ?

JG : The ceramics laboratory that I inherited at Lincoln Laboratory had high-temperature furnaces, a hand press, a hood, a powder x-ray diffractometer, and chemical benches. We were in the Digital Computer Division ; the Solid-state Division was much better equipped, but our access to their facilities was essentially non-existent as each person in that division had an agenda of their own. However, their mass spectrometer was a service facility to which we had access. We made routine transport measurements on the samples we prepared and characterized structurally. I developed a good working relationship with Jim Kafalas who had developed a high-pressure belt apparatus and was looking for something interesting to do with it. With him, John Longo and I demonstrated the relationship between bond-length mismatch in the perovskites and the hexagonal polytypes. Kafalas also developed high-pressure equipment for magnetic measurements with the vibrating-coil magnetometer. We used pressure to change from one polytype to another and to transform from high-spin to low-spin magnetic configurations. I came to appreciate the pressure variable as an extremely useful research tool. We also acquired sputtering equipment for the preparation of wavelength-selective films and for our MgO-Au composite film. At Lincoln, I relied primarily on developing chemical strategies that could provide important information with the measurement facilities at my disposal. I suppose that is why Oxford considered me as a solid-state chemist.

At Oxford, there was little money for equipment in the Inorganic Chemistry Laboratory. I was not given any significant start-up funding, so I relied on the availability of x-ray diffraction, facilities for chemical analysis, a glass-blowing shop and an electronics shop. I acquired furnaces for my own synthesis needs, the means to make impedance spectroscopy and routine electrochemical measurements as well as the optical equipment needed to study photo-electrolysis. The laboratory also had photoelectron spectroscopy and nuclear magnetic resonance, and I did some collaborations with those working with these instruments. Outdated equipment for electron paramagnetic resonance was put into use in the one systematic catalytic study I made on the phosphopolymolybdates. One group in the laboratory was given a second-hand vibrating-sample magnetometer that proved more frustrating than useful. At Oxford, I concentrated on ionic transport, battery cathodes, and photo-electrolysis ; I did relatively little work on the transition from localized to itinerant electronic behavior except to show that hybridization of the d electrons of a transition-metal atom with 6s2 core electrons of a counter cation could cause a localized electronic configuration to become delocalized.

AH : You just didn't have the infrastructure for magnetic measurements ? You couldn't have gone off and used magnetometers elsewhere in the university ?

JG : I suppose I could have developed a collaboration with someone in the Clarendon, but I was busy with another agenda.

AH : Were you a member of a College ?

JG : Yes, St. Catherine's.

AH : And were you able to build interdisciplinary connections through your college ?

JG : It should have been possible in principle, but it didn't turn out to be practical. When I arrived at the University of Texas at Austin, I was given $300 K as a start-up package and an empty room. Professor Hugo Steinfink had an x-ray diffraction laboratory that he has generously shared. He also had a high-pressure belt apparatus in disrepair that was a copy of the one developed by Kafalas at Lincoln Laboratory. I also had access to electron microscopes. With the help of post docs, I built up first my chemical facilities, including thermal analysis, impedance spectroscopy, a dry box, atomic absorption spectroscopy, an arbin battery tester, and equipment for routine electrochemical measurements. We do our own chemical analysis. We later added a SQUID magnetometer and an infrared image furnace for growing single crystals. J.-S. Zhou has developed measurement of transport and magnetic properties under pressure as well as specific-heat and thermal-conductivity measurements. Keqin Huang also developed apparatus for oxygen-permeation measurements. With our own synthetic facilities, we can develop our experimental strategies without relying on others. If you rely on getting crystals or samples from someone else, they have already done all the routine measurements on it. With only a special measurement technique, you must rely on collaborations. If you want to understand how physical properties vary with changing chemistry, you have to be able to make your own materials. I have always thought that was critical.

BBV : You never rely on others ?

JG : Occasionally we have received crystals that we could not prepare when others wanted us to collaborate by making measurements under pressure ; but for the most part we rely on our own samples designed to carry out a particular experimental strategy. People have also come to me for help in the interpretation of their data.

BBV : When you were at Oxford, did you have contact with other universities in England and Europe ?

JG : Yes. I went to Scotland to examine undergraduates. I also examined D. Phil. and Thèse d'Etat candidates in universities of England and France. I interacted some with Brian Steele of Imperial College, London, and his colleagues ; they were interested in the solid oxide fuel cell. At Cambridge, Sir Nevil Mott was interested in the transition from localized to itinerant electronic behavior, and Greenwood at Leeds was a solid-state chemist who did Mössbauer spectroscopy. At AERE Harwell, I collaborated in a European project with a Danish group on the development of lithium-ion batteries and an unsuccessful attempt to realize a methanol-air fuel cell. In France, the people in Montpellier were interested to interact on the subject of solid proton conductors, and I wrote a long review on iron oxides with Charles Gleitzer of Nancy. Hagenmuller sent me a young man from Bordeaux to work with me for over a year, and Jean Rouxel of Nantes sent me someone for six months. Pepe Fontcuberta came for a summer from Barcelona, and I had some interactions with electrochemists in Madrid. I was also asked to give a series of lectures at different universities in Norway on one occasion and in Germany on another. Emanuel Kaldish of the ETH in Switzerland arranged conferences for young people of the underdeveloped countries in Erice in Sicily, in New Delhi in India, in Cairo and Alexandria in Egypt. I also went to India, a country I have visited several times, as the Raman visiting professor.

BBV : And having this experience in Europe and the United States, do you have any idea why materials science generally never started in Europe as here although they have had a great tradition of solid-state chemistry ?

JG : The brief answer is our mission oriented defense and space efforts. England had a strong tradition in metallurgy and solid-state physics out of which grew a magnificent contribution to physical metallurgy. France and Holland had a strong tradition in magnetism out of which grew, secretly during World War II, the development of the ferrospinels that proved critical not only for the memory of the digital computer, but also for microwave devices. In this country, the development of the transistor was also seminal. Work on the nuclear bomb in Los Alamos and on radar at the Radiation Laboratory of MIT during the 1940s alerted the military people to the power of interdisciplinary research ; faced with the challenges of the Cold War, they encouraged this type of research in places like the Bell Telephone Laboratories, the Lawrence Livermore Laboratories, and the MIT Lincoln Laboratory. The military people also encouraged NSF to establish interdisciplinary materials laboratories in several of our universities. Bell Telephone had a monopoly in the early days, which enabled it to plough back its excess profits into research. In the 1950s and 1960s, the Bell Telephone Laboratories were the dominant player in the development of materials science both because of the changing nature of their business and because of large government contracts to develop military and space hardware. The development of fiber optics is an example of how their mission as a communications company kept them involved with materials problems. With the completion of the SAGE system at Lincoln Laboratory, IBM was chosen to manufacture the digital computers for it. The government allowed IBM to add 10% to the cost for product improvement ; they used these funds to build their Yorktown Heights research facility. Kennedy's decision to send a man to the moon within a decade added another set of materials problems that needed to be solved. Moreover, polymers were proving to be a great commercial success. It was the creation of mission-oriented laboratories and the technologies they spawned that challenged the traditional academic disciplines. Technical knowledge was being created rapidly outside of academia ; the traditional Metallurgy and Electrical Engineering departments were forced to expand their definition so as to include the new technologies and to prepare graduates for careers in these new types of laboratories. France under De Gaulle chose to become independent in military and space hardware, so a strong materials science effort was initiated in France under his leadership.

Also, during and following World War II, companies like DuPont de Nemours and Corning Glass had lively interdisciplinary research groups that produced numerous new products. It is unfortunate that most of these industrial facilities are now starved of corporate funds and must compete for government funding of their long-range targeted research.

The chemistry departments in the U. S. and Great Britain have been slow to build up solid-state chemistry as an interdisciplinary subject ; the inorganic chemistry community has been dominated by organometallic chemistry. The solid-state chemists have been incorporated into the materials science and engineering programs in the U. S. Only now as the engineers look for components at the molecular level are the chemistry departments becoming more involved. France, Holland, and Japan have recognized the importance of solid-state chemistry, but of course their development came only after a period of reconstruction following World War II. Russia has emphasized materials science as it, too, had military and space missions. Germany had a longer period of reconstruction, and their mission-oriented laboratories have all been industrial. The Max Planck Institutes are not mission oriented in the same way as the Department of Defense and Energy in this country, so materials science as we know it here has developed slowly in Germany.

Identity with a clear mission is important not only for the development of materials science, but also for the vitality of an interdisciplinary laboratory. For example, the MIT Lincoln Laboratory was the key player in the development of the digital computer during the 1950s. That success reflected a clear mission. When that mission was completed, the leadership lost its vision for further development of the digital computer, and therefore its most talented experienced staff in this field went elsewhere. By the end of the decade, it was clear that the future of the computer lay in making all the components smaller. Microelectronics was the next logical step. However, the Head of Lincoln Laboratory and the MIT administration did not wish to compete with industry in this next phase, so Ken Olsen took a group of computer engineers from the laboratory and founded the Digital Equipment Corporation. Others were given opportunities for leadership in several corporations. A few months later, a group of engineers who stayed with the laboratory had built a small computer that would be affordable by a single research unit. Wes Clark brought it down to the National Institute of Health where he solved in one afternoon a problem they had been working on for months. It was the first demonstration of the efficacy of a small computer. When he returned triumphant the next day, the Head of Lincoln Laboratory announced, "There will be no wet scientists in this laboratory." Consequently this innovative and motivated group left the laboratory.

On the other hand, there is also a strong cultural component. When I went to England, I found that members of the Inorganic Chemistry Laboratory downgraded targeted research ; "pure" research was only curiosity driven ! Moreover, I was astonished when a leader of a chemical industry told me they were hiring few people with a D. Phil degree because these people were only interested in "pure" research. This dichotomy between curiosity-driven and targeted research in a country where class distinctions are so important has, in my view, been a great impediment to Britain's development of materials science as we know it. In France, on the other hand, the Grandes Ecoles have been developing engineers for leadership posts. A British colleague acting as Director of the Institut Laue Langevin (ILL) laboratory in Grenoble told me that the British equipment salesmen knew everything about sales, but little about the performance of the equipment they were selling whereas the French salesmen were good engineers and could answer the specific questions posed by the experimental customer. France's delay in developing a strong presence in the field of materials science was largely due to the period of recuperation following World War II. Establishing the CNRS laboratories gave science a strong boost. However, the CNRS laboratories, like the Max Planck Institutes in Germany, tend to be built around an individual with a specific technique or area of specialization. They are rarely mission oriented unless they receive supplemental financial support from industry or a mission-oriented government agency. Nevertheless, they do build into the university structure the means to develop interdisciplinarity and thus to bid for targeted-research funds. Without the infrastructure of research scientists and equipment that the CNRS provides, the individual university professor with four or five students is isolated and generally unable to compete with larger groups in targeted research unless it is quite long-range.

BBV : Has it been possible for the European to do away with national identity ?

JG : There are now numerous large-science projects that are European rather than national, and science itself has an international character. However, cultural differences and national identities persist. The ILL in Grenoble, for example, is jointly supported by England, France, and Germany. The Director is rotated every three years between the three countries. Nevertheless, the groups from the different countries each bring a different style, sometimes to the irritation of one another. Also, Brussels funds projects that are required to be multinational. I had one with the French and Danes on batteries and had just negotiated another on fuel cells with the French and Germans when I returned to the U. S. These projects tend to be strategic, long-range, targeted research addressing fundamental materials problems. With the globalization of industry and a NATO alliance, the national barriers to cooperation are breaking down, but a national identity and competition for a market-share will accompany their European identity.

AH : You have just outlined the situation in the U. S., Britain, France, and Germany. Do you have any sense of how Japan fits into this process, or is that asking too much ?

JG : No. Japan has done a remarkable job in the area of materials science. The Japanese have not had a military mission, but they have realized their need to compete for external, high-technology markets. Therefore, they have set up mission-oriented government laboratories in support of their industries. They have also established interdisciplinary laboratories in association with universities ; these undertake the longer-range kinds of research that interests me. The large Tsukaba consortium is an interesting experiment that is well suited to the Japanese style. Japan is a homogenous society with a strong national identity ; its people strive to prove themselves after their defeat in World War II. They have built up an excellent cadre of scientists and engineers that is well supported with a sophisticated infrastructure of equipment ; and they make excellent measurements and theory. In my areas of interest, the Japanese are leading competitors and contributors. I am also happy that there are influential voices in Japan that are aware of our need to find a balance between nature's bounty and its exploitation by man.

AH : Now you are emphasizing the funding for equipment and the design of new instruments. I had the impression when you were talking about your own experience that you were de-emphasizing the role of instrumentation.

JG : I didn't mean to leave that impression. I emphasized the importance of being able to make your own materials if you wish to develop a chemical experimental strategy in materials science. I have used, for the most part, quite standard physical measurements because of the limitations of my own situation. However, where it was possible for me to develop instrumentation, I have supported it. Our most innovative instrumental developments have been in the area of high pressure. With Jim Kafalas, I used high-pressure synthesis of metastable phases and the measurement of magnetic properties under high pressure. Unfortunately my program at Lincoln Laboratory was terminated before I could fully exploit our facility. However, we did enough to attract J.-S. Zhou to Texas, and with him I have used pressure not only for the synthesis of metastable phases, but also as a variable to probe new electronic states in solids and transitions into or out of these states without changing the chemistry. Measurements made at the major national facilities are followed carefully ; they guide our strategies. I have already mentioned a number of these techniques.

AH : Can you point to instrumentation that has actually changed your trajectory, your research strategy, because you can now do things that you couldn't do before ?

JG : My research trajectory has been determined by questions I wanted to answer or by engineering challenges ; but of course the strategies we choose depend not only on our questions, but also on the facilities at our disposal. The advent of neutron diffraction, which allowed precise observation of the positions of lighter atoms such as oxygen as well as of ordered spin configurations, has certainly motivated much of my research even if the predictions made were to be confirmed experimentally by those with access to neutron diffraction. Similarly, the direct observation with high-resolution electron microscopy of extended defects such as shear planes and charge-density waves stimulated my research and clarified my view of solids. Access to high pressures has also allowed me to develop experimental strategies that have proven fruitful in my studies of phase transitions, especially high-spin to low-spin transitions and the crossover from localized to itinerant electronic behavior. I have made occasional use of Mössbauer spectroscopy. The development of the vibrating-sample, the vibrating-coil, and the SQUID magnetometer have played a central role. I should also mention that superconducting magnets have given us access to 50 kOe magnetizing fields that were, in 1951, restricted to a few centers. I have made less use of the laser, but the ability to deposit high quality films has been used from time to time. The ability to grow high-quality oxide single crystals with the IR image furnace has also shaped my strategies. Of course, we should not overlook the influence of computers on the automation of our experiments. The commercial availability of such instruments as Thermal Analysis or the Solartron have also enabled me to move into fields without having to build my own apparatus. Photoelectron spectroscopy is a technique that I have happily used whenever I could get access to it with a collaborative partner. The opportunity to find collaborators can be a great determinant to one's research trajectory.

AH : You have just told us about Japan. Do your Chinese colleagues give you any sense of what is going on in China ? Have you been to China ?

JG : Yes, I had the opportunity to make a fairly extensive visit to China a few years ago, and my colleague J.-S. Zhou keeps contacts there. The first observation is that China is changing rapidly. Under Mao Zedong the lid was on everything. Under Deng, people were allowed to make money, but politics remained tightly controlled. Under the present regime, people are more free to think as well as to make money, and the energies and imagination of the people has been unleashed, but within a nationalistic view and still restricted framework. The people value education. Western high-technology industries have moved their production facilities to China to have access to skilled, cheap labor. As a result, they are transferring manufacturing technical and managerial skills to China. The present government has decided it needs to compete with the world in high technology, so it is in the process of establishing research centers that are well-equipped with the latest tools. They have a big pool of educated talent, and they are beginning to bring back from the West with big salaries those they believe can lead their scientific as well as their technical development. China wishes to emerge as one of the leading countries in the science and technology arena. It is too early to tell how their investment will pay off. For the last 50 years, India has poured a substantial percentage of their gross national product into science and into technical education, but the return to the country has not been commensurate with the investment despite the emergence of excellent Indian scientists, many of whom work in the West. The political culture is extremely important.

AH : Have you seen the laboratories in China ?

JG : I was in China before the decisions were made to put a big investment into instrumentation in science research laboratories. I had no access to their military laboratories ; these were undoubtedly equipped first. At the time of my visit, researchers in the universities were not well equipped. Now the computer network and the cell telephones are as prevalent in the big cities as anywhere in the West.

In the last 30 years there has been a steady increase in the number of Asian students that come to this country for higher education. Many of them stay and make a wonderful contribution to our high-technology corporations and our schools. When I was younger, I was moved to wonder how the U. S. could best help the underdeveloped world to come into the technological age. I thought then we should be helping to set up research laboratories there, which is why I considered going to Iran in 1975. I have now come to realize that providing the opportunity to come to our graduate schools and the transfer of manufacturing facilities to their countries is a much more efficient method of providing help. But the political culture has to be right. It breaks your heart to see the conditions under which so many people struggle for life. Why hasn't Mexico taken off and done something more ? Why does a country like Argentina have 30% unemployment today ? It's sad. It shouldn't be. It shouldn't be like that.

Fin de l'enregistrement.

Pour citer l'entretien :

« Entretien avec John B. Goodenough », par Bernadette Bensaude et Arne Hessenbruch, mai 2001, Sciences : histoire orale, /spip.php ?article28.

Pour citer l'entretien :

« Entretien avec John B. Goodenough », par Bernadette Bensaude-Vincent et Arne Hessenbruch, mai 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article28.

Lieu : University of Texas, Austin (USA).

Support : enregistrement disque.

Transcription : Bernadette Bensaude-Vincent et Arne Hessenbruch.

Édition en ligne : Pierre Teissier