Enhancement of Critical Current Densities in Co-Doped BaFe$_{2}$As$_{2}$ with Columnar Defects Introduced by Heavy-Ion Irradiation

TL;DR

This study demonstrates that heavy-ion irradiation creates columnar defects in Co-doped BaFe$_{2}$As$_{2}$, significantly enhancing critical current densities and suppressing vortex creep, with implications for superconductor performance improvement.

Contribution

First demonstration of columnar defects in Co-doped BaFe$_{2}$As$_{2}$ via heavy-ion irradiation and analysis of their effects on superconducting properties.

Findings

Critical current density is strongly enhanced by irradiation.

Vortex creep rates are significantly suppressed.

Columnar defects confirmed by transmission electron microscopy.

Abstract

We report the first realization of columnar defects in Co-doped BaFe$_{2}$As$_{2}$ single crystals by heavy-iron irradiation. The columnar defects are confirmed by transmission electron microscopy and their density is about 40 % of the irradiation dose. Magneto-optical imaging and bulk magnetization measurements reveal that the critical current density is strongly enhanced in the irradiated region. We also find that vortex creep rates are strongly suppressed by the columnar defects. We compare the effect of heavy-ion irradiation into Co-doped BaFe$_{2}$As$_{2}$ and cuprate superconductors.