Magnetically induced splitting of a giant vortex state in a mesoscopic superconducting disk

TL;DR

This study demonstrates how a magnetic triangle can induce splitting of a giant vortex into individual vortices in a mesoscopic superconductor, with theoretical analysis confirming experimental observations.

Contribution

It reveals a novel magnetic control mechanism for vortex states in superconducting disks using a magnetic triangle and provides a theoretical explanation for the observed reentrant behavior.

Findings

Giant vortex splits into three vortices under magnetic influence.

Vortex configuration remains stable over a broad magnetic field range.

Theoretical Ginzburg-Landau analysis matches experimental results.

Abstract

The nucleation of superconductivity in a superconducting disk with a Co/Pt magnetic triangle was studied. We demonstrate that when the applied magnetic field is parallel to the magnetization of the triangle, the giant vortex state of vorticity three splits into three individual F0-vortices, due to a pronounced influence of the C3 symmetry of the magnetic triangle. As a result of a strong pinning of the three vortices by the triangle, their configuration remains stable in a broad range of applied magnetic fields. For sufficiently high fields, F0-vortices merge and the nucleation occurs through the giant vortex state. The theoretical analysis of this novel reentrant behaviour at the phase boundary, obtained within the Ginzburg - Landau formalism, is in excellent agreement with the experimental data.