Very strong intrinsic supercurrent carrying ability and vortex avalanches in (Ba,K)Fe2As2 superconducting single crystals

TL;DR

This study reveals that (Ba,K)Fe2As2 single crystals exhibit exceptionally strong intrinsic supercurrents, high vortex pinning potential, and vortex avalanches, making them promising for high-field superconducting applications.

Contribution

It demonstrates that (Ba,K)Fe2As2 single crystals have a high and field-independent pinning potential and a rigid vortex lattice, distinguishing them from cuprate superconductors.

Findings

Pinning potential U0 up to 10^4 K with little field dependence

Isotropic behavior and rigid vortex lattice at low temperatures and high fields

Observation of flux jumps indicating high critical current density

Abstract

We report that single crystals of (Ba,K)Fe2As2 with Tc = 32 K have a pinning potential, U0, as high as 10^4 K, with U0 showing very little field depend-ence. In addition, the (Ba,K)Fe2As2 single crystals become isotropic at low temperatures and high magnetic fields, resulting in a very rigid vortex lattice, even in fields very close to Hc2. The rigid vortices in the two dimensional (Ba,K)Fe2As2 distinguish this compound from 2D high Tc cuprate superconductors with 2D vortices, and make it being capable of cearrying very high critical current.Flux jumping due to high Jc was also observed in large samples at low temperatures.