Single crystals of lithium triborate LiB3O5 (LBO) have been grown by the top-seeded solution growth method with B2O3 as a solvent using different temperature gradients in the zone of crystallization. Optical and nonlinear optical properties of LBO single crystals have been investigated. The influence of post-growth thermal treatment in oxygen atmosphere on the optical properties has been studied.

The relaxation of diamagnetic magnetization in Bi2Sr2CaCu2Ox and YBa2Cu3Oy single crystals is studied in the temperature range 4.2 – 80 K in the magnetic field H = O, after the crystals have been subjected to fields of 2.5 and 6 T, respectively. The external magnetic field was perpendicular to the a–b plane of the crystals. The remanent magnetization Mr in both crystals is found to decrease logarithmically with time t (with the exception of the results in the temperature range 20 – 25 K for the bismuth crystal). The activation energy for motion of flux lines Uo is found to be − 10 – 15 meV (T < 20 K) and 110 – 130 meV (T > 20 K) for the bismuth crystal. For the yttrium crystal Uo ≈ 100 – 120 meV at T ≤ 70 K. These results are discussed in terms of the thermally activated flux motion model.

YBa2Cu3O7−χ single crystals with low impurity concentration and sizes up to 2x2x2 mm3 have been grown in a new type of ceramic crucible using both spontaneous crystallization and growth of a limited number of seeds on the yttrium oxide holder. The as-grown crystals reveal a superconducting transition with Toffc=89.8 K without additional annealing in oxygen.

The experimental technique for growing orthoferrite single crystals on seeds from the B2O3-BaF2-BaO melt is presented. Large high-quality single crystals of RFeO3 (R = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Y) have been grown and their growth conditions investigated. A quantitative estimate of Ba2+ ion substituted in the crystals is given.

Bulk single crystals of the superconducting YBa2Cu3O7−σ have been grown on a rotating crystal holder. The as-grown single crystals with maximum size 4×3×3 mm3 show superconducting transition temperature with Tonc=93 K and width ΔT0⩽0.3 K.

Regions of the ternary system B2O3-BaF2-BaO suitable for the flux growth of orthoferrite single crystals by the seeding technique have been studied. Physico-chemical properties of the fluxed melt based on this solvent have been investigated and crystallization parameters determined.

The temperature and field dependences of magnetization for Gd1-xSmxFeO3 single crystals have been measured. It is shown that the temperature of antiferromagnetic ordering of Gd3+ ions rises, while the effective field created by the d-subsystem on rare-earth ions decreases with increasing Sm3+ ion concentration.

An investigation was made of the mutual influence of ytterbium and neodymium ions on magnetic properties of Yb x Nd 1−x FeO 3 orthoferrites in a wide range of temperatures. The magnetic phase diagram was constructed and the boundary of spin-orientation transitions of the Γ 4 -Γ 42 -Γ 2 type in reverse compositions with a compensation point on the σ a (T) curves were determined. It was established experimentally that the presence of ytterbium ions had a dominant influence on the phase transition temperatures particularly in the case of those compositions which could be regarded as containing impurities