PREPARATION OF YBA2CU4O8 SINGLE-CRYSTALS IN Y2O3 CRUCIBLE USING O-2-HIP APPARATUS

YBa2Cu4O8 (Y-124) single crystals were grown by a self-flux method in a high-pressure gas mixture of 80% Ar-20% O-2. The calcined powder mix ture of Y-Ba-Cu-O at a ratio of Y:Ba:Cu = 1:8:20 was charged in a Y2O3 crucible and put into an O-2-HIP (hot isostatic pressing) apparatus. The heat-treatment at similar to 1150 degrees C under similar to 2000 atm was carried out. YBa2Cu4O8 single crystals with typical size of si milar to 0.1 X 0.2 x 0.05 mm(3) were obtained. The crystals exhibited a quite sharp superconducting transition at around 80 K. X-ray diffrac tion studies on the obtained crystals revealed that there are no stack ing faults and the crystal has the lattice parameters similar to those reported for powder samples prepared in a high-pressure oxygen gas. ( C) 1998 Elsevier Science B.V. All rights reserved.