Thermally activated spontaneous fluxoid formation in superconducting thin film rings.
We have observed spontaneous fluxoid generation in thin film rings of the amorphous superconductor Mo3Si, cooled through the normal-superconducting transition, as a function of quench rate and externally applied magnetic field, using a variable sample temperature scanning SQUID microscope. Our results can be explained using a model of freeze-out of thermally activated fluxoids, mediated by the transport of bulk vortices across the ring walls. This mechanism is complementary to a mechanism proposed by Kibble and Zurek, which only relies on causality to produce a freeze-out of order parameter fluctuations.
Kirtley
J R
JR
IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598, USA.
Tsuei
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Tafuri
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