THE EFFECT OF ANNEALING ON STACKING-FAULTS AND J(C) VALUES OF PMP PROCESSED YBCO

Highly textured YBCO bulk materials with dense stacking faults were prepared by the powder melting process (PMP). We re-annealed the samples at temperatures between 800 degrees C and 900 degrees C to reduce the stacking faults in YBa2Cu3Oy (123) crystals. The microstructural characteristics of these samples were investigated by SEM and TEM, and their critical current densities were estimated from magnetization hysteresis loops. The results indicate that both the density of stacking faults and the J(c) values decrease considerably after the reheat treatments. The reasons for the elimination of stacking faults by annealing the specimens at high temperature are discussed.