Thickness dependence of structural and transport properties of Co-doped BaFe2As2 on Fe buffered MgO substrates

TL;DR

This study explores how the thickness of Co-doped BaFe2As2 superconducting films affects their structural and transport properties, revealing that increased thickness improves transition temperature and texture quality, with implications for vortex pinning.

Contribution

It demonstrates the relationship between film thickness and strain relief, texture development, and critical current density in Co-doped BaFe2As2 films on Fe-buffered MgO substrates.

Findings

Thicker films show higher superconducting transition temperatures.

An additional 110 textured component appears in films thicker than 90 nm.

The 110 textured component may enhance c-axis vortex pinning.

Abstract

We have investigated the influence of the superconducting layer thickness, d, on the structural and transport properties of Co-doped BaFe2As2 films deposited on Fe-buffered MgO substrates by pulsed laser deposition. The superconducting transition temperature and the texture quality of Co-doped BaFe2As2 films improve with increasing d due to a gradual relief of the tensile strain. For d>90 nm an additional 110 textured component of Co-doped BaFe2As2 was observed, which leads to an upward shift in the angular dependent critical current density at H // c. These results indicate that the grain boundaries created by the 110 textured component may contribute to the c-axis pinning.