FLUX-DENSITY DISTRIBUTION IN BI2SR2CACU2OX AND ITS CRITICAL CURRENT

Flux density distribution of Bi2Sr2CaCu2Ox sintered specimens prepared by partial melt process (critical temperature T(c) approximately 90 K) was observed by a magneto-optical method using iron garnet films at various temperatures. The flux penetration and trapping processes were inhomogeneous, reflecting that the specimens consist of an assemblage of laminated grains without preferential orientation. It was found that flux hardly penetrates into the center of the specimen, though the flux density distribution is inhomogeneous. Critical current J(c), estimated from the averaged flux penetration using Bean's model, was nearly equal to that estimated from magnetization. These results indicate that the regions with high critical current connect directly with each other without weak-link in Bi2Sr2CaCu2Ox specimens prepared by partial melt process.