Studies on AC susceptibility of superconductors with finite thickness

Abstract

The magnetic moment, flux and current profiles, hysteresis loops, AC susceptibilities of superconductors with finite thickness in perpendicular magnetic field have been calculated by means of the Brandt method, which can be applied to arbitrary cross-section and arbitrary current voltage characteristics E(j). Detailed results are presented for rectangular cross-sections 2a X 2b and power-law electric field E(j) = Ec(j/jc)n, thus taking into account the flux creep effects. AC susceptibilities (ACS) of infinite long superconductors in parallel magnetic field, which are usually used to compare with experimental data, have also been calculated by numerically solving the flux creep equation ∂B/∂t = -∂(Bν)/∂x. The results indicate that when compared with experimental data, ACS of infinite long samples are not a good approximation and ACS of samples with finite thickness should be used. © 1999 Elsevier Science B.V. All rights reserved.