Magnetization in a generalized critical-state model for type-II superconductors

Abstract

This paper describes the magnetization of type-II superconductors in the critical state, where the critical current density, J c has a field dependence of the form J c (B) = J 0 /(1 + B/B 0 ) n . Explicit formulae are derived for the various branches of the complete high-field hysteresis loop. The geometry under consideration is that of an infinitely long rectangular bar placed in a parallel applied field. In the discussion, emphasis is put on the behaviour of the vertical width, ΔM, of the hysteresis loop, and a simple graphical method to fit model parameters to experimental data is outlined.