Critical currents and magnetization properties of YBCO prepared by MPMG process

Abstract
YBaCuO prepared by the Melt-Powder-Melt-Growth (MPMG) process has high critical current density over 30,000 A/cm2 at 77K and 1T. It has been found that non-superconducting Y2BaCuO5 (211) particles dispersed in the 123 superconducting phase are responsible for high Jc values. The values of critical current densities increased with increasing the volume fraction of the 211 particles. An anomalous second peak was observed in magnetization loops for some samples which showed a broad Tc transition in AC measurements, suggesting that some kinds of defects are responsible for the peak.