HIGH CRITICAL CURRENTS IN PERITECTICALLY GROWN YBA2CU3O7-X SINGLE-CRYSTALS

Large single crystals of YBa2Cu3O7-x are grown from ceramic pellets by a peritectic growth mechanism. SEM and microprobe analysis show a high defect density of Y2BaCuO5 precipitates and microcracks. The anisotropic magnetic properties of peritectic grown crystals are compared with those of more perfect eutectic crystals grown from the flux. Magnetization loops measured with a vibrating sample magnetometer are used for the estimation of the anisotropic critical current densities. Peritectic grown crystals show higher critical current densities with smaller anisotropy than eutectic grown crystals. These results are confirmed by torque magnetometer measurements.