Laboratory of Magnetic Materials
The Laboratory of Magnetic Materials is headed by Candidate of Phys. and Math. Sciences Leonard Bezmaternykh
Since late 70s the scientific problems connected with crystal formation of oxide compounds in multicomponent solution-melt systems have been the main directions of the Laboratory activity. In the fundamental aspect, crystal formation is studied, first of all, as a process of phase transformations at the transition of a system from one state of thermodynamic equilibrium to another. On this basis, approaches to crystallization control are being advanced; technologies of single crystal growth for physical studies and technical applications are being developed; techniques of solution-melt crystallization application for search of new materials are being improved.
Among the basic Laboratory achievements there is the development of technologies of group growth of ferrite single crystals by using baric-borate solution-melts. Along with high reproducibility of properties of single crystals being grown, these technologies stand out for their cost efficiency and environmental safety. They have been introduced into production at Russian industrial plants.
The development of technology of group growth of yttrium ferrogarnet single crystals has been supported by the US Civil Research & Development Foundation (CRDF grant RZ2-504, 1997) that evidences the universal recognition of this work. In the framework of this method of crystallization control, the role of thermophysical and hydrodynamic excitations in formation of growth streakiness of yttrium ferrogarnet single crystals has been clarified; the influence of the growth streakiness on excitation and propagation of magnetoelastic and magnetostatic waves has been studied.
The technique of the on-line control of homogeneity and magnetic Q-factor of single crystals by parameters of variable delay on magnetoelastic waves has been suggested. On the basis of the advance approach the high-quality laser single crystals of a gadolinium- gallium garnet with nearly one-centered distribution of active ions Nd3+ have been grown; the generation on four new transitions has been excited.
For the first time, incongruently melting piezoelectric single crystals of lead and barium ferrogallogermanates have been obtained. On Nd3+ doped trigonal lead gallogermamate single crystals with disordered structure generation characteristics under the condition of diode pumping have been studied. New solutions-melts based on bismuth and lithium molybdates have been investigated as media for growing single crystals of rare earth aluminum galloferroborates. They surpass other known solutions-melts by determining crystallization parameters.
On grown single crystals of rare earth ferroborates with typical for them quasi-unidimensional distribution of magnetic cations, the cycle of works on physics of magnetism and magnetoelectric interactions has been performed. High temperature multiferroics based on rhombic Fe2-xGaxO3 have been synthesized.
Complex investigations of properties of synthesized single crystals are being carried out jointly with the leading national and foreign scientific centers.
The most significant results of scientific activity are included into the following publications:
- L.N. Bezmaternykh, V.G. Mashchenko, N.A. Sokolova and V.L. Temerov. Growth of iron-garnet single crystals on rotating carrier from BaO-B2O3 fluxes, J. of Crystal Growth, v.69, №2-3,(1984) p.407
- L.N. Bezmaternykh, V.G. Mashchenko, N.A. Sokolova and V.L. Temerov. Interaction of Magnetostatic and Magnetoelastic Waves with Growth Inhomogeneities in Iron Garnet Single Crystals, Phys. Stat.Sol.(a), 72(1982), p. 469.
- I.A. Gudim, L.N. Bezmaternykh and A.F. Bovina. Crystallization of Ba3Fe2Ge4O14 and Ba2Fe2GeO7 in Oxide-Fluoride flux, Crystallography Reports, v. 50, Suppl. 1, 2005, p. 106.
- S. G. P. Strohmaier, H. J. Eichler, K. S. Alexandrov, L. N. Bezmaternykh, I. A. Gudim, A. A. Kaminskii. Pb3Ga2Ge4O14:Nd3+ crystal - a novel nonlinear laser material, Phys. Status Sol. A, 202, № 10 (2005), p. 111-112.
Monocrystals of garnets