Isaak Konstantinovich Kikoin (born 28.03.1908) is a Soviet experimental physicist and an academician (1953; corresponding member 1943). He was born in the town of Zhagary. He graduated from the Leningrad Polytechnic Institute (1930). In 1927-36 he worked at the Leningrad Physico-Technical Institute, and in 1936—43 at the Urals Physico-Technical Institute, where he also headed the department of physics at the Polytechnic Institute (Sverdlovsk). In 1943, when work in the field of atomic science and technology was launched in this country, he was one of the first physicists with whom I. V. Kurchatov began the analysis and development of the whole complex of the atomic problem. He took an active part in setting up the laboratory which was then transformed into the Institute of Atomic Energy, where he works to this day. At the same time he has been professor at Moscow University (from 1955).
His research concerned solid-state physics, atomic and nuclear physics and nuclear engineering. He carried out important studies of the electrical and magnetic properties of metals and semiconductors. In 1931 — 33 he measured the Hall effect and the electrical conductivity of liquid metals in a magnetic field; in 1933 he began a series of studies of the influence of a magnetic field on photoelectric effects in semiconductors, which in the same year ended in the discovery, together with M. M. Noskov, of a new phenomenon, the photomagnetoelectric effect (the Kikoin–Noskov effect). Studying the Hall effect in ferromagnets, he found in them, alongside the ordinary effect, an anomalous Hall effect as well, connected with the magnetisation of the ferromagnet; later he found this effect in paramagnetic metals too. He was the first to prove the presence of the galvanomagnetic effect in liquid metals, and he determined the magnitude of the gyromagnetic ratio in semiconductors, which was of great importance for the theory of electrical conductivity and of the magnetic properties of substances.
He developed methods of measuring electrical quantities at large steady currents and built a new type of ammeter for measuring very strong currents.
Having concentrated his research at the beginning of the 1940s on a new field, he leads the work in one of the principal directions of the atomic problem and has become I. V. Kurchatov's closest associate. He made a significant contribution to the development of Soviet atomic science, technology and industry.
In 1956—65 he carried out extensive studies of the photomagnetic effect in single crystals of germanium and silicon and discovered the anisotropy of this effect. In 1964 he detected the photopiezoelectric effect and continued his studies of galvanomagnetic phenomena in ferromagnets; in 1966 he was the first to observe quantum oscillations of the photomagnetic effect at low temperatures. He discovered an anomalously large Hall effect in the chromium — tellurium alloy. In studying the effect of ionisation on the properties of semiconductors he found new effects, the so-called radiation electromagnetic and piezoelectric effects.
In recent years he has done much towards drawing up physics syllabuses and textbooks for secondary schools and for higher education.
Twice Hero of Socialist Labour (1951, 1978), the Lenin Prize (1959), USSR State Prizes (1942, 1949, 1951, 1953, 1967, 1980). The I. V. Kurchatov Gold Medal (1971), the P. N. Lebedev Prize (1979).