B. B-V. So where did you start? You graduated in chemistry, no?
J. B. G. 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?"
B. B.-V. It was really encouraging.
J. B. G. 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.
A. H. What year was that?
J. B. G. 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.
A. H. When did you find this out?
J. B. G. 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.
So this is how you came to study oxides?
|A perovskite structure:
For a QuickTime movie of a rotating perovskite crystal, click here.
J. B. G. 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.
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.
A. H. And this realization came to you in the mid 1950's?
J. B. G. 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.
A. H. What an interesting managerial technique.
J. B. G. 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.
A. H. Do you remember when that was? Do you remember the year?
J. B. G. I believe it was 1956 or 1957.
B. B.-V. So you stayed at the MIT Lincoln Laboratory for that?
J. B. G. 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.
B. B-V. Which one? Metallic Oxides?
J. B. G. 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.
A. H. & B. B-V. When was this?
J. B. G. It was about 1970. So I had had about 12 years from 1958 to 1970 to do fundamental research.
A. H. Was all of this done at Lincoln Laboratory? Were you involved in the organization of the Department of Materials Science and Engineering at MIT?
J. B. G. 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.
A. H. But there is a gap of more than a year because the energy crisis was in 1973.
J. B. G. 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.
A. H. Why didn't you want to do nuclear?
J. B. G. 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.
B. B-V. Who chose that name? What was the name of your colleague who coined the word NASICON?
J. B. G. 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.
A. H. When was this?
J. B. G. 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.
B. B-V. So you abandoned your Iranian project?
J. B. G. I did.
B. B-V. And the $7 M?
J. B. G. 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.
A. H. Is that what the Oxford Inorganic Chemistry Laboratory was interested in?
J. B. G. 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.
B. B.-V. When did you come up with this new oxide?
J. B. G. In 1994.
B. B.-V. So it is fairly recent. Were you still in Oxford?
J. B. G. 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.
B. B.-V. So you have a laboratory facility here?
J. B. G. 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.
A. H. They model it on the computer?
J. B. G. 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.
A. H. 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.
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.
A. H. So you don't go to many conferences either?
J. B. G. 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.
B. B-V. Over your career, you seem to have migrated from one discipline to another, finally coming back to where you started.
J. B. G. 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.
B. B.-V. Do you think of yourself as a physicist, or a solid-state chemist or...
J. B. G. I am a solid-state scientist.
A. H. Don't you identify with any of the established categories?
J. B. G. 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.
B. B.-V. That's like the story about Einstein who is a Jew in Germany, but he was a German in Switzerland.
J. B. G. Well, that's life.
B. B.-V. Yes, it's life. But you have been publishing in several journals.
J. B. G. 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 J. Solid-state Chemistry, in the J. 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.
B. B-V. I understand you have strong links with the solid-state chemistry community.
J. B. G. 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.
B. B.-V. So finally the physicists are accepting you?
J. B. G. Yes, but sometimes I think a bit reluctantly by some.
A. H. And you also publish in Nature.
J. B. G. Yes, I publish in Nature.
B. B-V. Have you had any links with the people in Grenoble?
J. B. G. 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.
B. B.-V. And what are your relations with Professor Paul Hagenmuller? He is in exactly the same field as you.
J. B. G. 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.
A. H. Why is that?
J. B. G. 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.
B. B-V. But the solid-state community is small here.
J. B. G. 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.
A. H. It seems that you have had quite a lot of contact with the Chinese and Japanese.
J. B. G. I see you have done a lot of homework.
A. H. We can see Chinese and Japanese names on your publications in the last five years.
J. B. G. 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.
A. H. So the Japanese with whom you had contact were all in the university world; it wasn't SONY or another corporation?
J. B. G. 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.
A. H. You allowed them to do that?
J. B. G. 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.
B. B.-V. Does it cover equipment as well as students?
J. B. G. Not permanent equipment, but expendables.
B. B.-V. You said you were interested in developing materials that would perform an engineering function. Do you go after research for industrial development?
J. B. G. 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.
B. B-V. 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?
J. B. G. 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.
A. H. But isn't the market the ultimate driver?
J. B. G. 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.
B. B.-V. 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.
J. B. G. 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.
B. B.-V. Do you think you have contributed more to electrodes or to electrolytes?
J. B. G. 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.
B. B.-V. And what is your opinion about a specialized journal for the community of researchers working on solid-state ionics?
J. B. G. 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.
B. B.-V. 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?
J. B. G. 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.
A. H. 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?
J. B. G. That 's a big question.
A. H. Maybe you could start by saying what was available in 1951 when you started.
J. B. G. 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.
A. H. So what was the infrastructure of the Lincoln Laboratory, of Oxford, and here in Texas?
J. B. G. 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.
A. H. You just didn't have the infrastructure for magnetic measurements? You couldn't have gone off and used magnetometers elsewhere in the university?
J. B. G. I suppose I could have developed a collaboration with someone in the Clarendon, but I was busy with another agenda.
A. H. Were you a member of a College?
J. B. G. Yes, St. Catherine's.
A. H. And were you able to build interdisciplinary connections through your college?
J. B. G. 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.
B. B.-V. You never rely on others?
J. B. G. 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.
B. B.-V. When you were at Oxford, did you have contact with other universities in England and Europe?
J. B. G. 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.
B. B.-V. 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?
J. B. G. 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.
B. B.-V. Has it been possible for the European to do away with national identity?
J. B. G. 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.
A. H. 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?
J. B. G. 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.
A. H. 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.
J. B. G. 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.
A. H. 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?
J. B. G. 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.
A. H. 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?
J. B. G. 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.
A. H. Have you seen the laboratories in China?
J. B. G. 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.