Magnetization Jump in a Model for Flux Lattice Melting at Low Magnetic Fields

TL;DR

This paper investigates the flux lattice melting transition at low magnetic fields using a frustrated XY model, revealing a magnetization jump linked to vortex proliferation and dissipation, consistent with experimental observations.

Contribution

It provides a numerical analysis of flux lattice melting in low fields, highlighting the magnetization jump and vortex proliferation as key features.

Findings

Magnetization exhibits a sharp jump at the melting transition.

Vortex-antivortex pairs and vortex loops proliferate at the transition.

Results align qualitatively with recent experimental data.

Abstract

Using a frustrated XY model on a lattice with open boundary conditions, we numerically study the magnetization change near a flux lattice melting transition at low fields. In both two and three dimensions, we find that the melting transition is followed at a higher temperature by the onset of large dissipation associated with the zero-field XY transition. It is characterized by the proliferation of vortex-antivortex pairs (in 2D) or vortex loops (in 3D). At the upper transition, there is a sharp increase in magnetization, in qualitative agreement with recent local Hall probe experiments.