Magnetization of mesoscopic superconducting discs

TL;DR

This paper investigates the magnetic behavior of small superconducting discs using coupled Ginzburg-Landau and Maxwell equations, revealing complex transitions and vortex states that align with recent experimental observations.

Contribution

It introduces a three-dimensional modeling approach that incorporates finite thickness, providing more accurate predictions of magnetization and vortex states in mesoscopic superconducting discs.

Findings

Identification of first and second order transitions depending on disc size.

Observation of multiple vortex states with different angular momenta.

Agreement of theoretical magnetization curves with experimental data.

Abstract

Solutions of Ginzburg-Landau eqns. coupled with three dimensional Maxwell eqns. reveal intriguing magnetic response of small superconducting particles, qualitatively different from the two dimensional approximation but in agreement with recent experiments. Depending on the radius and thickness first or second order transitions are found for the normal to superconducting state. For a sufficient large radius of the disc several transitions in the superconducting phase are obtained which correspond to different angular momentum giant vortex states. The incorporation of the finite thickness in the calculation is crucial in order to obtain agreement with the position and the size of these jumps, and the line shape and magnitude of the magnetization curves.