Critical Current Density and Its Hysteresis in Magnetic Field for Ba-Y-Cu-O Films Prepared by a Sputtering Technique

Abstract
A considerably large transport critical current density J c (1.2×105 A/cm2 at 4.2 K and 15 T) was observed for the superconducting Ba-Y-Cu-O thin films prepared by an rf sputtering method. In association with such a large J c, the hysteresis of J c against the applied magnetic field was smaller compared to that in bulk samples prepared by a solid phase reaction method. It was considered that a fairly smooth morphology of grain boundaries in the thin films improved superconducting properties. The hysteresis of J c was discussed on the basis of the weak link model.