Flux-cutting and flux-transport effects in type-II superconductor slabs in a parallel rotating magnetic field

TL;DR

This paper investigates how type-II superconductor slabs respond magnetically to in-plane rotating magnetic fields using various flux-line-cutting models, revealing oscillatory and stable magnetization behaviors depending on the field strength.

Contribution

It applies multiple flux-line-cutting models to explain experimental magnetization behaviors in rotating magnetic fields, providing new insights into flux dynamics in type-II superconductors.

Findings

Magnetization oscillates when applied field is below penetration threshold.

Magnetization becomes stable at large rotation angles when field exceeds penetration threshold.

Magnetic induction profiles inside the superconductor are characterized.

Abstract

The magnetic response of irreversible type-II superconductor slabs subjected to in-plane rotating magnetic field is investigated by applying the circular, elliptic, extended-elliptic, and rectangular flux-line-cutting critical-state models. Specifically, the models have been applied to explain experiments on a PbBi rotating disk in a fixed magnetic field ${\bm H}_a$, parallel to the flat surfaces. Here, we have exploited the equivalency of the experimental situation with that of a fixed disk under the action of a parallel magnetic field, rotating in the opposite sense. The effect of both the magnitude $H_a$ of the applied magnetic field and its angle of rotation $\alpha_s $ upon the magnetization of the superconductor sample is analyzed. When $H_a$ is smaller than the penetration field $H_P$, the magnetization components, parallel and perpendicular to ${\bm H_a}$, oscillate with increasing the rotation angle. On the other hand, if the magnitude of the applied field, $H_a$, is larger than $H_P$, both magnetization components become constant functions of $\alpha_s$ at large rotation angles. The evolution of the magnetic induction profiles inside the superconductor is also studied.