Critical current density distribution and magnetization loss in YBCO coated conductors

Abstract

Lateral distributions of the critical current density (Jc) in YBCO coated conductors were measured by the magnetic knife method. It was observed that Jc decreased near the edges of the coated superconductors. By considering the measured lateral distributions and the magnetic field dependence of Jc, electromagnetic field analyses were performed to calculate the magnetization losses in the coated superconductors subjected to an AC transverse magnetic field. The calculated and measured magnetization losses were in good agreement. Deviations of the measured magnetization losses from the analytical values based on a uniform Jc distribution can be explained by non-uniform Jc distributions in actual coated superconductors. Larger loss generation mechanism in YBCO coated conductors with non-uniform Jc distributions at small magnetic field was revealed by temporal evolutions of current density, magnetic flux density, and electric field in the numerical analyses.