Magneto-opitcal studies of a c-oriented epitaxial MgB2 film show that below 10 K the global penetration of vortices is dominated by complex dendritic structures abruptly entering the film. We suggest that the observed behavior is due to a thermo-magnetic instability which is supported by vortex dynamics simulations. The instability is also responsible for large fluctuations in the magnetization curves in MgB2 at low temperatures.
@article{arxiv.cond-mat/0104113,
title = {Dendritic magnetic instability in superconducting MgB2 films},
author = {T. H. Johansen and M. Baziljevich and D. V. Shantsev and P. E. Goa and Y. M. Galperin and W. N. Kang and H. J. Kim and E. M. Choi and M. -S. Kim and S. I. Lee},
journal= {arXiv preprint arXiv:cond-mat/0104113},
year = {2009}
}
Comments
Extended version: 4 pages, 7 figures, submitted to PRL, for high-quality MO images see http://www.fys.uio.no/faststoff/ltl/results/biology/index.html