Enhanced current flow through meandering and tilted grain boundaries in YBCO films

TL;DR

This study shows that specific grain boundary geometries in YBCO films, like meandering and tilting, can enhance current flow and critical current density, improving superconductor performance.

Contribution

It demonstrates that grain boundary geometry influences current flow in YBCO films, revealing that meandering and tilted boundaries can increase critical current density.

Findings

Meandering GBs lead to higher Jc compared to straight GBs.

Tilted GBs exhibit different flux entry behavior under current.

Current-induced flux entry is observed in meandering GBs.

Abstract

Grain boundaries (GBs) have been shown to limit critical current density, Jc, in YBa2Cu3O7 (YBCO) coated conductors. Here we use transport measurements and scanning Hall probe microscopy coupled with current reconstruction to demonstrate that GB geometry, such as the in-plane meandering observed in films grown by metalorganic deposition (MOD) on rolling assisted biaxially textured substrate (RABiTS), can lead to higher GB Jc. We observe current-induced flux entry into such a coated conductor, then model its behavior by imaging films with single, straight GBs tilted at various angles to the applied current.