Magneto-optical imaging reveals that in superconducting films of MgB2 a transport current creates avalanche-like flux dynamics where highly branching dendritic penetration patterns are formed. The instability is triggered when the current exceeds a threshold value, and the superconductor, shaped as a long strip, is initially in the critical state. The instability exists up to 19 K, which is a much wider temperature range than in previous experiments, where dendrites were formed by applying a magnetic field. The instability is believed to be of thermo-magnetic origin indicating that thermal stabilization may become crucial in applications of MgB2.
@article{arxiv.cond-mat/0201260,
title = {Current-induced dendritic magnetic instability in superconducting MgB2 films},
author = {A. V. Bobyl and D. V. Shantsev and T. H. Johansen and W. N. Kang and H. J. Kim and E. M. Choi and S. I. Lee},
journal= {arXiv preprint arXiv:cond-mat/0201260},
year = {2009}
}