SINGLE CRYSTAL GROWTH OF HIGH TEMPERATURE SUPERCONDUCTORS AND INVESTIGATION OF THEIR PHYSICAL PROPERTIES

Part of the phase diagram of the La2O3-CuO system has been studied and single crystals of La2CuO4, (LaSr)2CuO4 (up to 20 × 8 × 6 mm3), YBa2Cu3O7−δ (up to 8 × 6 × 0.1 mm3) and HoBa2Cu3O7-(up to 3 × 2.5 × 1 mm3) have been grown by the method of spontaneous crystallisation, using a rotational crucible. It has been established that thermal treatment of "123" single crystals under oxygen pressure to 10 bars improves their superconducting properties. Electrical, magnetic, optical properties, and the real structure of the single crystals produced have been studied.