Theory of flux motion with backflow current in high- superconductors

Abstract

Based upon the well-known normal-core model for flux line in high- superconductors and by correctly taking into account the backflow current due to both pinning forces and other vortices, we developed a theory for flux motion in the framework of the Bardeen-Stephen and Nozières-Vinen approaches. We derived analytically the longitudinal resistivity xx and the Hall resistivity xy as functions of the magnetic field in the region of flux flow. Our results explain qualitatively all the essential features of recent experiments on xy, including, in particular, the observed negative Hall resistivity at low magnetic field in certain high-Tc superconductors. Furthermore, a long-standing problem concerning the expressions for the viscous-drag force and the applied force on a vortex is discussed and clarified. © 1992 The American Physical Society.