Effect of microstructures on critical current density of textured YBa2Cu3Oy

Textured YBa2Cu3Oy(YBCO) bulk samples with Jc of magnitude of 105 A/cm2 were prepared by different melt procession (MP). Microstructure was examined by means of XRD, SEM and TEM. Very fine particles were observed by TEM. Transport critical current density, hysteresis and magnetization relaxation measurements for the samples show that the Jc and its field dependence vary significantly for the samples in LN2 and in fields up to 2 Tesla. The experiment shows that the quantity and quality of grain boundary is still very important for high Jc of MP YBCO.