Vortex-Antivortex annihilation dynamics in a square mesoscopic superconducting cylinder

TL;DR

This study simulates vortex-antivortex annihilation in a mesoscopic superconducting cylinder with an antidot, revealing how size, temperature, and material parameters influence vortex dynamics and annihilation locations.

Contribution

It provides a detailed simulation of vortex-antivortex interactions in a mesoscopic superconductor, highlighting the effects of geometry and parameters on annihilation behavior.

Findings

Vortex-antivortex encounter location depends on sample size and temperature.

Vortex and antivortex velocities vary over time during annihilation.

Magnetization and order parameter topology change during vortex dynamics.

Abstract

The dynamics of the annihilation of a vortex-antivortex pair is investigated. The pair is activated magnetically during the run of a simulated hysteresis loop on a square mesoscopic superconducting cylinder with an antidot inserted at its center. We study the nucleation of vortices and antivortices by first increasing the magnetic field, applied parallel to the axis of the sample, from zero until the first vortex is created. A further increase of the field pulls the vortex in, until it reaches the antidot. As the polarity of the field is reversed, an antivortex enters the scene, travels toward the center of the sample and eventually the pair is annihilated. Depending on the sample size, its temperature, and Ginzburg-Landau parameter, the vortex-antivortex encounter takes place at the antidot or at the superconducting sea around it. The position and velocity of the vortex and antivortex singularities were evaluated as a function of time. The current density, magnetization and order parameter topology were also calculated.