Critical fields for vortex expulsion from narrow superconducting strips

TL;DR

This paper calculates the critical magnetic fields for vortex expulsion in narrow superconducting strips using Ginzburg-Landau theory, comparing results with London theory and experiments, showing better agreement for narrow geometries.

Contribution

It provides a detailed calculation of vortex expulsion fields in narrow strips using Ginzburg-Landau formalism, improving upon previous London theory predictions and aligning with experimental data.

Findings

Critical fields for vortex expulsion are identified and characterized.

Ginzburg-Landau predictions align better with experiments for narrow strips.

Two critical fields are distinguished based on vortex stability.

Abstract

We calculate the critical magnetic fields for vortex expulsion for an infinitely long superconducting strip, using the Ginzburg-Landau formalism. Two critical fields can be defined associated with the disappearance of either the energetic stability or metastability of vortices in the center of the strip for decreasing magnetic fields. We compare the theoretical predictions for the critical fields in the London formalism with ours and with recently published experimental results. As expected, for narrow strips our results reproduce better the experimental findings.