Influence of pinning centers of different natures onsurrounding vortices

TL;DR

This study uses time-dependent Ginzburg-Landau theory to analyze how different types of pinning centers affect vortex behavior and superconducting properties in mesoscopic superconductors, revealing how defect nature influences vortex dynamics and critical fields.

Contribution

It introduces a comparative analysis of three defect configurations and their impact on vortex dynamics and critical fields in mesoscopic superconductors using advanced simulation methods.

Findings

Lower critical field is unaffected by defect type.

Vertices of through holes reduce local superconductivity degradation.

Type-III defects can precisely control vortex dynamics.

Abstract

Studies involving vortex dynamics and their interaction with pinning centers are an important ingredient to reach higher critical currents in superconducting materials. The vortex distribution around arrays of engineered defects, such as blind and through holes, may help to improve the superconducting properties. Thus, in this work, we used the time-dependent Ginzburg-Landau theory to investigate the vortex dynamics in superconductors of mesoscopic dimensions with a large central square defect with three different configurations: (i) a hole which passes through the sample (interface with the vacuum); (ii) a superconducting region with lower critical temperature (Tc); and (iii) a region with a more robust superconductivity, i.e., with a higherTc. Such systems can be envisaged as elementary building blocks of a macroscopic decorated specimen. Therefore, we evaluated the influence of different interfaces on the vortex dynamics and their effects in the field-dependent magnetization and time-dependent induced electric potential variation. The results show that the lower critical field is independent from the nature of the defect. However, the currents crowd at the vertices of the through hole producing a lower degradation of the local superconductivity, which may increase the upper critical field. On the other hand, the last type of defect can be used to control the vortex dynamics in the main superconducting region around the defect with more accuracy. Whereas the first two defects are attractive for the vortices, the third type is repulsive for them, being needed several vortices penetrated in the superconducting matrix to have vortices penetrated into it.