Identification of stacking faults with flux pinning in powder melting processed YBa2Cu3Oy

Highly textured YBCO samples with different densities of stacking faults are prepared by a powder melting process (PMP). Microstructural examination using transmission electron microscopy (TEM) is conducted on the samples. The dc transport critical currents at 77 K in applied magnetic fields up to 22 T and magnetization hysteresis loops at temperatures, between 60 and 90 K in magnetic fields up to 7 T are measured with a SQUID magnetometer. The irreversibility lines are obtained from measurements of magnetoresistance. The results indicate that the stacking faults strongly influence the flux pinning behavior of the melt processed YBCO superconductors in magnetic fields up to 22 T.