Critical current anisotropy in relation to the pinning landscape

Abstract

The critical current of superconductors is determined by the interaction of vortices with the intrinsic and extrinsic defects in the material. Analyzing the critical current density to produce structure-property relationships has not proved easy for the anisotropic superconductors. The difficulty partly results from having two sources of anisotropy, the anisotropy in the vortex cross section and the anisotropy of the defects themselves. In this chapter we survey models of superconductor behavior which have been used to elucidate the structure property relationships. These include scaling approaches such as Blatter scaling and variations on this approach. We then look at more direct models of pinning behavior and the difficulties these models encounter. Finally we examine probabilistic or maximum entropy modelling as a means to understand the relationship between critical currents and the pinning landscape.