Boris I. Kochelaev (to 75th anniversary)

April, 19, 2009 is the 75th anniversary of Boris Ivanovich Kochelaev, Editor-in-Chief of MRSej, Professor at Kazan State University, the leading scientist in the field of spin dynamics in condensed matter, the brightest representative of the Kazan Physical School founded by the corresponding-member of USSR Academy of Sciences S.A. Al’tshuler.

Born in 1934 in the working settlement DirizhablStroi (now Dolgoprudny city in the Moscow region) Boris I. Kochelaev graduated with the silver medal the secondary school in the city of Vyatskie Polyany (Kirov’s region) and entered to the Physical-Mathematical Faculty at Kazan State University in 1952.

The scientific research activities of B. I. Kochelaev started during his students’ years under supervision of S.A. Al’tshuler and then continued on PhD courses at the Chair of Experimental and Theoretical Physics (1957-1960). After getting the PhD degree at Kharkov University, Boris I. Kochelaev took the positions of assistant professor, associate professor and full professor of the Chair of Theoretical Physics at Kazan State University. He headed this Chair during 27 years (1973-2000). During more than 40 years B.I. Kochelaev is the leading lecturer at Physics Department, he has developed the lecture courses on quantum theory of solids, non-equilibrium thermodynamics and quantum statistical physics. These courses are considered as the basic education courses for the theoretical physics students. The period for two terms in Harvard University (1963-1964) had a great impact on the scientific interests of B. I. Kochelaev. In Harvard University, under supervision of the future Nobel Prize winner professor N. Bloembergen, he solved the problem of conduction electron spin polarization and electron correlations influence on indirect exchange interactions between paramagnetic impurities in metals. In 1967 B.I. Kochelaev got the Doctoral Degree with the thesis “The theory of dynamic effects in paramagnetic crystals”.

The scientific works of B.I. Kochelaev in sixties and seventies were devoted to studies of spin-phonon interactions in paramagnetic crystals. He proposed original theories of non-resonant absorption and resonant dispersion of the hypersound in a paramagnetic media, the indirect spin-spin interactions between paramagnetic ions caused by conduction electrons in semiconductors and mediated by phonons in insulators, the nuclear spin relaxation caused by electronic spin-spin interactions at ultra-low temperatures, investigated the manifestations of the dispersion of crystal vibrational spectra in the Jahn-Teller effect, derived the theory of the coupled spin-phonon excitations and determined the conditions for their appearance. Together with L.K. Aminov, B.I. Kochelaev investigated interactions between paramagnetic centers via phonons with taking into account the retardation effects. This work had the essential influence on further development of the theories of interactions between localized electrons mediated by static and dynamic crystal lattice deformations. Further investigations of non-linear phenomena in paramagnets irradiated by radio-frequency fields, light and hypersound resulted in the theory of kinetic processes in paramagnetic crystals based on the spin temperature concept. In the framework of this theory it appeared to be possible to explain the experimentally observed phonon avalanche under saturation on the wing of the electron paramagnetic resonance (EPR) line. Also the theory of light scattering in paramagnetic insulators was developed, and the experimentally observed super-scattering of light under saturation on the wing of the EPR line was explained. B.I. Kochelaev predicted the observed later effect of non-resonant sound absorption and its giant amplification by radio-frequency fields.

Together with his PhD students, B.I. Kochelaev proposed the theory of EPR and spin relaxation in conventional superconductors with paramagnetic impurities. It has been shown that the spin dynamics and magnetic properties of impurity superconductors are determined mainly by existence of the coupled spin excitations of the conducting and localized electrons as well as by appearance of long-range correlations between paramagnetic impurities. In the framework of this theory the whole set of rather unusual experimental data on EPR in conventional superconductors obtained by the group headed by E.G. Kharakhashyan in Kazan Physical-Technical Institute was explained.

In recent years the scientific activities of B.I. Kochelaev lie in the most “hot” topics of condensed matter physics, namely, in the physics of strong-correlated electron systems. He proposed to use paramagnetic probes inside CuO2 planes to measure relaxation rates of magnetization in high-Tc superconductors. The idea of Kochelaev has been successfully realized in the joint investigations with the group headed by Prof. B. Elshner in Darmstadt University. Further investigations based on the proposed method in collaboration with the group headed by the Nobel Prize winner Prof. K. A. Muller in Zurich University allowed to understand the nature of very fast electron spin relaxation and to propose the model for the observed phase separation onto nanoscale metal and insulator domains in CuO2 planes.

Low-dimensional magnets and the role of antiferromagnetic fluctuations have been investigated by B.I. Kochelaev together with his PhD student S.I. Belov. They proposed a new approach based on idea about spin waves in the media with topological excitations (skyrmions) and described in the framework of a single model static and dynamic parameters of layered magnets such as spin coherence length, magnetic susceptibility, nuclear spin relaxation rate etc.

In the last years the works of B. I. Kochelaev in collaboration with the groups headed by Prof. K. von Nidda and Prof. Lloidl were devoted to the EPR investigations of the electron spin kinetics in substances with giant magnetoresistance. Together with the group headed by Dr. J. Sichelschmidt in Dresden, EPR spectra in heavy-fermion compounds below Kondo temperature were studied.

The investigations of B.I. Kochelaev devoted to the theory of nuclear and electron spin-lattice relaxation, to the theory of magnetic resonance phenomena in insulators, metals and superconductors are well known in the world. He has been invited to the numerous international, All-Union and All-Russian conferences and scientific schools with plenary talks. B.I. Kochelaev founded his own scientific school. He supervised 31 PhD students, among which 9 got the Doctoral degree, became the professors (in Russia, Germany and USA).

During many years B.I. Kochelaev is the chairperson in the Council for PhD and Doctoral degree awarding, the member of the International Committee of Scientific Society AMPERE. The Red Banner Order and the Order of the Honor, the State Award of Tatarstan Republic for science and technology awarded him. B.I. Kochelaev is the Honored Scientist of Russian Federation and Tatarstan Republic, the Honored Professor of Kazan State University.

The colleagues at Physics Department respect his active civil standpoints on many problems of scientific and public life and many times trusted him to be their representative in the Council of Kazan State University.

Last years the headed by B.I. Kochelaev Scientific School on Magnetic Resonance in Condensed Matter was recognized as the Leading Scientific School supported by the President of Russian Federation. The members of School congratulate their colleague, teacher and friend, Prof. Boris Ivanovich Kochelaev with the 75th anniversary and wish him to be in a strong health and in a good mood and to be successful in all fields of his activity.

Colleagues,  friends and disciples.