Strong Tc dependence for strained, epitaxial Ba(Fe1-xCox)2As2 thin films

TL;DR

This study investigates how strain affects the superconducting transition temperature (Tc) in epitaxial Ba(Fe1-xCox)2As2 thin films, revealing a strong dependence linked to structural distortions, with potential for higher Tc in strained films.

Contribution

It demonstrates a clear correlation between strain-induced structural changes and Tc in epitaxial Ba(Fe1-xCox)2As2 films, suggesting pathways to enhance superconducting temperatures.

Findings

Tc increases from 16.2 K to 24.5 K with strain

Epitaxial growth achieved on multiple substrates

Higher Tc may be attainable with increased strain

Abstract

Ba(Fe1-xCox)2As2 superconducting thin films have been grown on SrTiO3, (La,Sr)(Al,Ta)O3, LaAlO3 and YAlO3 (YAO) single crystal substrates by pulsed laser deposition. All the films, except on YAO, have been grown epitaxially without buffer layers. The films deposited on YAO contained 45 degree in-plane rotated grains and showed a broad superconducting transition. The onset Tc of the films is observed to increase from 16.2 K to 24.5 K with increasing c/a, mainly due to a slight distortion of the AsFe4 tetrahedron. From this correlation, we expect that higher superconducting transition temperatures than 24.5 K in a strained epitaxial film may be possible.