Magnetic Behavior and Effect of Transport Current on It in Superconducting Nb-Zr Wire

Abstract

The magnetic behaviors of superconducting Nb-Zr (25%) wire have been studied at 4.2°K. The magnetization curve exhibits an irreversible behavior. In transverse fields the magnetization is reduced due to the transport current, but in longitudinal fields the influence of the transport current is not recognized. The results are explained by a phenomenological model for inhomogeneous type II superconductors. The model, based on Ginzburg-Landau-Abrikosov-Gor'kov (GLAG) theory, was proposed by Silcox and Rollins and extended by the authors to consider a pinning effect of imperfections on fluxoids. The calculated magnetization curve is in good agreement with the experimental values. The influence of the transport current is qualitatively explained by introducing the Lorentz force on fluxoids due to current into the theory. The dependence of critical current density of a short wire sample on an applied field is also calculated and compared with the experimental values.