ENCYCLOPÆDIA BRITANNICA
Bardeen, John
b. May 23, 1908, Madison, Wis., U.S.
d. Jan. 30, 1991, Boston, Mass.
American physicist who was cowinner of the Nobel Prize for Physics in both 1956 and 1972. He shared the 1956 prize with William B. Shockley and Walter H. Brattain for their joint invention of the transistor. With Leon N. Cooper and John R. Schrieffer he was awarded the 1972 prize for development of the theory of superconductivity.
Bardeen earned bachelor's and master's degrees in electrical engineering from the University of Wisconsin (Madison) and obtained his doctorate in 1936 in mathematical physics from Princeton University. A staff member of the University of Minnesota, Minneapolis, from 1938 to 1941, he served as principal physicist at the U.S. Naval Ordnance Laboratory in Washington, D.C., during World War II.
After the war Bardeen joined (1945) the Bell Telephone Laboratories in Murray Hill, N.J., where he, Brattain, and Shockley conducted research on the electron-conducting properties of semiconductors. On Dec. 23, 1947, they unveiled the transistor, which ushered in the electronic revolution. The transistor replaced the larger and bulkier vacuum tube and provided the technology for miniaturizing the electronic switches and other components needed in the construction of computers.
In the early 1950s Bardeen resumed research he had begun in the 1930s on superconductivity, and his Nobel Prize-winning investigations provided a theoretical explanation of the disappearance of electrical resistance in materials at temperatures close to absolute zero. The BCS theory of superconductivity (from the initials of Bardeen, Cooper, and Schrieffer) was first advanced in 1957 and became the basis for all later theoretical work in superconductivity. Bardeen was also the author of a theory explaining certain properties of semiconductors. He served as a professor of electrical engineering and physics at the University of Illinois, Urbana-Champaign, from 1951 to 1975.
Cooper, Leon N.
b. Feb. 28, 1930, New York, N.Y., U.S.
American physicist and winner of the 1972 Nobel Prize for Physics, along with John Bardeen and John Robert Schrieffer, for his role in developing the BCS (for their initials) theory of superconductivity. The concept of Cooper electron pairs was named after him. Cooper was educated at Columbia University, receiving his Ph.D. in 1954. He taught at Ohio State University in Columbus before joining (1958) the faculty at Brown University, Providence, R.I., where he was appointed Henry Ledyard Goddard university professor in 1966 and Thomas J. Watson, Sr., professor of science in 1974.
His principal contribution to the BCS theory was the discovery (1956) that electrons, which under normal conditions repel each other, are attracted to each other in superconductors, a phenomenon termed the Cooper electron pairs.
He lectured extensively abroad and took a special interest in teaching physics to humanities students. His publications include An Introduction to the Meaning and Structure of Physics (1968), Introduction to Methods of Optimization (1970), and Methods and Applications of Linear Programming (1974).
b. May 31, 1931, Oak Park, Ill., U.S.
American physicist and winner, with John Bardeen and Leon N. Cooper, of the 1972 Nobel Prize for Physics for developing the BCS theory (for their initials), the first successful microscopic theory of superconductivity.
Schrieffer was educated at the Massachusetts Institute of Technology, Cambridge, and the University of Illinois, Urbana-Champaign, where he received his Ph.D. in 1957. He was a young graduate student working under Bardeen at the University of Illinois when he helped explain why metals lose their electrical resistance at very low temperatures.
Schrieffer taught at the University of Chicago (1957-59) and the University of Illinois (1959-62) before joining the faculty of the University of Pennsylvania, Philadelphia, where in 1964 he was named Mary Amanda Wood professor of physics. Schrieffer was Andrew D. White professor at large at Cornell University (1969-75) and from 1980 was professor of physics at the University of California, Santa Barbara. He published Theory of Superconductivity in 1964.
b. March 7, 1900, Breslau, Ger. [now Wroclaw, Pol.]
d. March 30, 1954, Durham, N.C., U.S.
German-American physicist who, with Walter Heitler, devised (1927) the first quantum mechanical treatment of the hydrogen molecule.
London was educated at the universities of Bonn, Frankfurt, Göttingen, Munich (Ph.D., 1921), and Paris. He was a Rockefeller research fellow at Zürich and Rome and a lecturer at the University of Berlin. From 1933 to 1936 he was a research fellow at the University of Oxford and then went to the University of Paris as master and director of research.
In 1939 he immigrated to the United States to become professor of theoretical chemistry at Duke University, Durham, N.C., and from 1953 he was James B. Duke professor of chemical physics there. He became a U.S. citizen in 1945. His publications include two volumes on Superfluids (1950, 1954).
London's theory of the chemical binding of homopolar molecules marked the beginning of modern quantum mechanical treatment of the hydrogen molecule and is considered one of the most important advances in modern chemistry. With his brother, Heinz London, he developed (1935) the phenomenological theory of superconductivity, providing a new foundation for the understanding of molecular forces and clarifying the connection between pure quantum phenomena and many of the most striking facts of chemistry.
b. Sept. 21, 1853, Groningen, Neth.
d. Feb. 21, 1926, Leiden
Dutch winner of the Nobel Prize for Physics in 1913 for his work on low-temperature physics and his production of liquid helium. He discovered superconductivity, the almost total lack of electrical resistance in certain materials when cooled to a temperature near absolute zero.
From 1871 until 1873 Kamerlingh Onnes studied and worked at Heidelberg University, notably with the German physicists Robert Bunsen and Gustav Kirchhoff. Awarded a doctorate by the University of Groningen (1879), he taught at the Polytechnic School in Delft (1878-1882). From 1882 to 1923 he served as professor of experimental physics at the University of Leiden.
Influenced by the work of Johannes van der Waals, Kamerlingh Onnes investigated the equations describing the states of matter and studied the general thermodynamic properties of liquids and gases over a wide range of pressures and temperatures. He founded (1894) and built up the Cryogenic Laboratory (now known by his name) that established Leiden as the low-temperature research centre of the world. From 1895 to 1906 he concentrated on
perfecting cryogenic experimental techniques and studied metals and fluids at low temperatures. Having built an improved hydrogen-liquefaction machine two years previously, he succeeded in liquefying helium in 1908. His attempts to solidify helium were fruitless until Willem Hendrik Keesom, his student and successor as director of the Kamerlingh Onnes Laboratory, achieved the feat in 1926.
Kamerlingh Onnes also demonstrated that the resistance of some electrical conductors disappears suddenly at a temperature near absolute zero (-273º C), and he termed this phenomenon "superconductivity." His systematic researches on superconductivity (begun in 1911) were of extreme importance because of their bearing on the theory of electrical conduction in solids.
b. May 16, 1950, West Germany
In full JOHANNES GEORG BEDNORZ German physicist who, along with Karl Alex Müller, was awarded the 1987 Nobel Prize for Physics for their joint discovery of superconductivity in certain substances at temperatures higher than had previously been thought attainable.
Bednorz graduated from the University of Münster in 1976 and earned his doctorate at the Swiss Federal Institute of Technology at Zürich in 1982. That same year he joined the IBM Zürich Research Laboratory, where he was recruited by Müller into the latter's studies of superconductivity.
In 1983 the two men began systematically testing newly developed ceramic materials known as oxides in the hope that such substances could act as superconductors. In their efforts Bednorz was the experimenter in charge of the actual making and testing of the oxides. In 1986 the two men succeeded in achieving superconductivity in a barium-lanthanum-copper oxide at a temperature of 35 kelvins (-238º C [-396º F]), 12 K higher than the highest temperature at which superconductivity had previously been achieved in any substance.
b. April 20, 1927, Basel, Switz.
In full KARL ALEXANDER MÜLLER Swiss physicist who, along with J. Georg Bednorz, was awarded the 1987 Nobel Prize for Physics for their joint discovery of superconductivity in certain substances at higher temperatures than had previously been thought attainable.
Müller received his doctorate from the Swiss Federal Institute of Technology in 1958, and beginning in 1963 he performed research in solid-state physics at the IBM Zürich Research Laboratory, heading the physics department there for several years and becoming an IBM fellow in 1982.
A specialist in the ceramic compounds known as oxides, Müller in the early 1980s began searching for substances that would become superconductive (i.e., conduct electricity with no resistance) at higher temperatures than had theretofore been obtained. The highest transition temperature (the temperature below which a material loses all electrical resistance) attainable at that time was about 23 K (-250º C [-418º F]). In 1983 Müller recruited Bednorz to help him systematically test various oxides, materials that a few recent studies had indicated might be suitable for superconductivity. In 1986 the two men succeeded in achieving superconductivity in a recently developed barium-lanthanum-copper oxide at a temperature of 35 K (-238º C [-396º F]), 12 K higher than had previously been achieved. Their discovery immediately prompted a wave of renewed superconductivity experiments by other scientists worldwide, this time using oxides, and within a year transition temperatures approaching 100 K (-173º C [-280º F]) had been achieved.
The intense research generated by Müller's and Bednorz's discovery raised the prospect that superconductivity could be achieved at temperatures high enough for the generation and transmission of electric power, a feat that would have important economic implications.
Josephson, Brian D.
b. Jan. 4, 1940, Cardiff, Glamorgan, Wales
In full BRIAN DAVID JOSEPHSON British physicist whose discovery of the Josephson effect while a 22-year-old graduate student won him a share (with Leo Esaki and Ivar Giaever) of the 1973 Nobel Prize for Physics.
He entered Trinity College, Cambridge, in pursuit of an education in physics and received his bachelor's (1960) and master's and Ph.D. degrees (1964) there, publishing his first work while still an undergraduate; it dealt with certain aspects of the special theory of relativity and the Mossbauer effect. He was elected a fellow of Trinity College in 1962. He was a brilliant and assured student; one former lecturer recalled a special need for precision in any presentation to a class that included Josephson--otherwise, the student would confront the instructor politely after class and explain the mistake.
While still an undergraduate, Josephson became interested in superconductivity, and he began to explore the properties of a junction between two superconductors that later came to be known as a Josephson junction. Josephson extended earlier work in tunneling, the phenomenon by which electrons functioning as radiated waves can penetrate solids, done by L. Esaki and I. Giaever. He showed theoretically that tunneling between two superconductors could have very special characteristics, e.g., flow across an insulating layer without the application of a voltage; if a voltage is applied, the current stops flowing and oscillates at high frequency. This was the Josephson effect. Experimentation confirmed it, and its confirmation in turn reinforced the earlier BCS theory of superconductor behaviour. Applying Josephson's discoveries with superconductors, researchers at International Business Machines Corporation had assembled by 1980 an experimental computer switch structure, which would permit switching speeds from 10 to 100 times faster than those possible with conventional silicon-based chips, increasing data processing capabilities by a vast amount.
He went to the United States to be a research professor at the University of Illinois in 1965-66 and in 1967 returned to Cambridge as assistant director of research. He was appointed reader in physics in 1972 and professor of physics in 1974. He was elected a fellow of the Royal Society in 1970.
A few years before the Nobel award, Josephson grew interested in the possible relevance of Eastern mysticism to scientific understanding. In 1980 he and V.S. Ramachandran published an edited transcript of a 1978 international symposium on consciousness at Oxford under the title Consciousness and the Physical World.