Flux pinning in a slab model of grain and twin boundaries

Abstract

The flux pinning potential and critical current of a grain and a twin boundary are evaluated for a S-S’-S junction model and a configuration of parallel magnetic field and junction plane. In the grain boundary model, the S’ domain is assumed to be disordered, to mimic oxygen disorder. Large critical currents ≈O(106 amp/cm2) are estimated for both models. The grain boundary model exhibits a “nonweak” link behavior and moderate critical current dependence on the grain misalignment angle. We briefly dicuss an approach to enhance critical currents based on our grain boundary model.