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.
@article{arxiv.1002.2095,
title = {Very strong intrinsic supercurrent carrying ability and vortex avalanches in (Ba,K)Fe2As2 superconducting single crystals},
author = {Xiao-Lin Wang and S. R. Ghorbani and Sung-Ik Lee and S. X. Dou and C. T. Lin and T. H. Johansen and Z. X. Cheng and G. Peleckis and K. Muller and M. Shabazi and G. L. Sun and D. L. Sun},
journal= {arXiv preprint arXiv:1002.2095},
year = {2015}
}