Vortex matter in superconducting mesoscopic disks: Structure, magnetization, and phase transitions

TL;DR

This paper investigates the structure, magnetization, and phase transitions of vortex matter in mesoscopic superconducting disks, revealing first-order and second-order phase transitions and identifying vortex glass states through theoretical calculations and comparison with experiments.

Contribution

It provides a detailed theoretical analysis of vortex configurations and magnetization behavior in mesoscopic disks, highlighting the presence of vortex glass states and phase transition characteristics.

Findings

Magnetization shows first-order transitions as vortices change by one.

Identification of vortex glass states separated by second-order transition.

Comparison with experiments confirms traces of vortex glass in magnetization data.

Abstract

The dense vortex matter structure and associated magnetization are calculated for type-II superconducting mesoscopic disks. The magnetization exhibits generically first-order phase transitions as the number of vortices changes by one and presents two well-defined regimes: A non-monotonous evolution of the magnitude of the magnetization jumps signals the presence of a vortex glass structure which is separated by a second-order phase transition at $H_{c2}$ from a condensed state of vortices (giant vortex) where the magnitude of the jumps changes monotonously. We compare our results with Hall magnetometry measurements by Geim et al. (Nature 390, 259 (1997)) and claim that the magnetization exhibits clear traces of the presence of these vortex glass states.