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Current-induced dendritic magnetic instability in superconducting MgB2 films

A. V. Bobyl·D. V. Shantsev·T. H. Johansen·W. N. Kang·H. J. Kim·E. M. Choi·S. I. Lee
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Abstract

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.

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A. V. Bobyl, D. V. Shantsev, T. H. Johansen, W. N. Kang, H. J. Kim, E. M. Choi, S. I. Lee. 2002-04-12. Current-induced dendritic magnetic instability in superconducting MgB2 films. https://doi.org/10.1063/1.1485304

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