Phase transition of vortex states in two-dimensional superconductors under a oscillating magnetic field from the chiral helimagnet

TL;DR

This study explores how vortex states in two-dimensional superconductors respond to oscillating magnetic fields from chiral helimagnets, revealing unique transition behaviors distinct from uniform fields.

Contribution

It introduces a detailed analysis of vortex behavior under oscillating magnetic fields using Ginzburg-Landau equations, highlighting novel vortex transition phenomena.

Findings

Vortices appear simultaneously across all regions with increasing magnetic field.

Vortex transitions differ from those under uniform magnetic fields.

Small uniform fields can remove down-vortices efficiently.

Abstract

We have investigated vortex states in two-dimensional superconductors under a oscillating magnetic field from a chiral helimagnet. We have solved the two-dimensional Ginzburg-Landau equations with finite element method. We have found that when the magnetic field from the chiral helimagnet increases, vortices appear all at once in all periodic regions. This transition is different from that under the uniform magnetic field. Under the composite magnetic field with the oscillating and uniform fields (down-vortices), vortices antiparallel to the uniform magnetic field disappear. Then, the small uniform magnetic field easily remove down-vortices.