Influence of the sample geometry on the vortex matter in superconducting microstructures

TL;DR

This study investigates how the shape of mesoscopic superconductors influences vortex behavior, revealing that geometry significantly affects vortex expulsion but only weakly impacts vortex penetration, with implications for understanding vortex stability.

Contribution

It provides experimental insights into the role of sample geometry on vortex dynamics in superconducting microstructures, highlighting differential effects on penetration and expulsion.

Findings

Vortex penetration is weakly affected by internal vortex configuration.

Vortex expulsion is strongly controlled by vortex pattern stability.

The $H-T$ diagram shows transitions between different vorticity states.

Abstract

The dependence of the vortex penetration and expulsion on the geometry of mesoscopic superconductors is reported. Hall magnetometry measurements were performed on a superconducting Al square and triangle. The stability of the vortex patterns imposed by the sample geometry is discussed. The field-temperature $H-T$ diagram has been reconstructed showing the transitions between states with different vorticity. We have found that the vortex penetration is only weakly affected by the vortex configuration inside the sample while the expulsion is strongly controlled by the stability of the vortex patterns. A qualitative explanation for this observation is given.