Angular dependent vortex pinning mechanisms in YBCO coated conductors and thin films

TL;DR

This study compares the angular dependence of vortex pinning in YBCO films on different substrates, revealing that defect density influences pinning strength and that more defective films can outperform less defective ones.

Contribution

It demonstrates that vortex pinning mechanisms are consistent across substrates but vary in extent due to defect density, challenging the notion that single crystal performance sets an upper limit.

Findings

Pinning regimes are consistent across different substrates.

Higher defect density enhances vortex pinning.

IBAD films outperform single crystal films in critical current density.

Abstract

We present a comparative study of the angular dependent critical current density in YBa2Cu3O7 films deposited on IBAD MgO and on single crystal MgO and SrTiO3 substrates. We identify three angular regimes where pinning is dominated by different types of correlated and uncorrelated defects. We show that those regimes are present in all cases, indicating that the pinning mechanisms are the same, but their extension and characteristics are sample dependent, reflecting the quantitative differences in texture and defect density. In particular, the more defective nature of the films on IBAD turns into an advantage as it results in stronger vortex pinning, demonstrating that the critical current density of the films on single crystals is not an upper limit for the performance of the IBAD coated conductors.