Disorder effects on the superconducting properties of BaFe$_{1.8}$Co$_{0.2}$As$_2$ single crystals

TL;DR

This study investigates how neutron irradiation-induced defects affect the superconducting transition temperature, critical field anisotropy, and critical current densities in BaFe$_{1.8}$Co$_{0.2}$As$_2$ single crystals, revealing notable enhancements in current capacity.

Contribution

It provides new insights into the effects of neutron irradiation on iron-based superconductors, specifically showing how defects influence key superconducting properties.

Findings

Critical current densities increased up to threefold.

Superconducting transition temperature decreased by about 0.3 K.

Upper critical field anisotropy reduced from 2.8 to 2.5 at 22 K.

Abstract

Single crystals of superconducting BaFe$_{1.8}$Co$_{0.2}$As$_2$ were exposed to neutron irradiation in a fission reactor. The introduced defects decrease the superconducting transition temperature (by about 0.3 K) and the upper critical field anisotropy (e.g. from 2.8 to 2.5 at 22 K) and enhance the critical current densities by a factor of up to about 3. These changes are discussed in the context of similar experiments on other superconducting materials.