Weak link property in superconducting Y-Ba-Cu-O prepared by QMG process

摘要

The weak link property in a QMG (quench and melt growth)-processed single-grain Y-Ba-Cu-O specimen was investigated by measuring the dependence of the critical current density on temperature, history of magnetic field application, and its enhancement under a longitudinal field geometry. The results show that weak-link regions still remain in the specimen. It is speculated that these link regions, which can transport superconducting currents at low temperatures, are degraded with increasing temperature and lose superconductivity around 20 K.