Critical Current Density of Melt(QMG)-Processed YBa_2Cu_3O_x Bulk Superconductors(High-T_c Superconducting Materials Research)
Upper critical fields and critical current densities were measured for melt(QMG)-processed YBa_2Cu_3O_x bulk superconductors by four probe method. The QMG material has high critical values as a bulk superconductor. However, the controlling factors of these values are complicated. It was suggested from a measurement of angular dependence of J_c upon the directions of applied magnetic fields that the J_c value was not described by a simple flux pinning. It was thought that the pinning by small defects such as layered structure, twin boundaries and oxygen deficiencies and the suppressing of current flow such as micro cracks small angle grain boundaries play an important role in the J_c of QMG bulk superconductors.
- Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy
Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy 37 (1/2), 190-197, 1992-11