Magnetic responses of a high-Tc semi-reversible YBCO superconductor

We report the magnetic responses of a YBCO superconducting sample prepared by solid-state reaction method, in terms of d.c. magnetization, and a.c. susceptibility. Hysteresis loops have been analyzed in the framework of critical state model including the Meissner current. The critical current as a function of temperature and the volume fraction of the grains have been estimated from the a.c. susceptibility data. The zero resistance temperature and diamagnetic onset temperature were found to be 90 and 91.5 K respectively. (orig.)