CALCULATION OF MAGNETIC-FLUX PROFILES AND DEDUCTION OF CRITICAL CURRENT DENSITIES FOR TYPE-II SUPERCONDUCTORS

The critical state concept for the calculation of internal flux profiles in type II superconductors is used to model the magnetization behaviour of high T(c) materials. In this application of the model, the field dependent reversible magnetization, and critical current density are incorporated flexibly into numerical solutions of the basic equations. The solutions are compared to results obtained by using the Bean (constant J(c)) and Kim (field dependent J(c)) approximations. We use theoretically calculated magnetization curves to analyse recently published, and also our own, experimental magnetization data for bulk, textured Y/ErBaCu0 samples. Pitfalls and guidelines when using such measurements to obtain intrinsic material critical current densities are discussed.