Enhancement of pinning properties of superconducting thin films by graded pinning landscapes

TL;DR

This study demonstrates that graded pinning landscapes in superconducting thin films enhance critical current and suppress avalanches, highlighting the importance of non-uniform pinning for improved superconducting performance.

Contribution

It introduces and experimentally investigates graded pinning landscapes in superconducting films, showing their effectiveness in enhancing pinning and stability.

Findings

Increased critical current at high temperatures and low fields.

Suppressed thermomagnetic avalanches at low temperatures.

Enhanced pinning efficiency due to non-uniform landscapes.

Abstract

A graded distribution of pinning centers (antidots) in superconducting MoGe thin films has been investigated by magnetization and magneto-optical imaging. The pinning landscape has maximum density at the border, decreasing progressively towards the center. At high temperatures and low fields, where this landscape mimics the vortex distribution predicted by the Bean model, an increase of the critical current is observed. At low temperatures and fields, the superconducting performance of the non-uniform sample is also improved due to suppression of thermomagnetic avalanches. These findings emphasize the relevance of non-uniform pinning landscapes, so far experimentally unexplored, on the enhancement of pinning efficiency.