Scaling behaviour of the critical current in clean epitaxial Ba(Fe1-xCox)2As2 thin films

TL;DR

This study investigates the angular dependence of critical current and upper critical field in epitaxial Ba(Fe1-xCox)2As2 thin films, revealing intrinsic pinning effects and evidence for multi-band superconductivity.

Contribution

It provides detailed measurements of Jc(theta) and Hc2(theta), demonstrating intrinsic pinning and temperature-dependent anisotropy in these superconducting films.

Findings

No Jc(theta) peaks for H || c observed.

Jc(theta) shows a broad maximum at theta=90°, indicating intrinsic pinning.

Mass anisotropy increases with temperature, supporting multi-band superconductivity.

Abstract

The angular-dependent critical current density, Jc(theta), and the upper critical field, Hc2(theta), of epitaxial Ba(Fe1-xCox)2As2 thin films have been investigated. No Jc(theta) peaks for H || c were observed regardless of temperatures and magnetic fields. In contrast, Jc(theta) showed a broad maximum at theta=90 degree, which arises from intrinsic pinning. All data except at theta=90 degree can be scaled by the Blatter plot. Hc2(theta) near Tc follows the anisotropic Ginzburg-Landau expression. The mass anisotropy increased from 1.5 to 2 with increasing temperature, which is an evidence for multi-band superconductivity.