Improvement of Critical Current Density in YBa2Cu3O6+x Superconductor by Sn Addition

Abstract
When SnO2 was added to Y-123 (YBa2Cu3O6+x ) powder and sintered at 1223 K for 86.4 ks, the densification was enhanced remarkably, and the density reached 99% of the theoretical value for the 2-mol%-SnO2-added specimen, while the average grain size became smaller with Sn addition. Fine spherical BaSnO3 precipitates were observed to be distributed in the grains and at grain boundaries. The AC magnetization measurements indicated that Sn addition causes intragrain J c m to increase at 77 K in the magnetic field between 0.02 and 0.12 T. The J c m exceeded 106 A/cm2 at 0.04 T for the 3-mol%-SnO2-added specimen.