Correlation between grain and grain-boundary critical current densities in ex situ coated conductors with variable YBa2Cu3O7−δ layer thickness

Abstract

The dependence of the percolative critical current density at low magnetic fields on YBa2Cu3O7−δ (YBCO) layer thickness is studied by comparing grain, JcG, and grain-boundary, JcGB, critical current densities for a series of ex situ processed YBCO films on a RABiTS template. Both critical current densities decrease as a function of thickness and the values of JcG and JcGB show a clear correlation which suggests the existence of an interaction between Abrikosov–Josephson vortices on the grain boundaries and Abrikosov vortices in the bulk of the grains. This opens the possibility to improve JcGB by optimizing the pinning capabilities of the grains.