title: Thermally activated spontaneous fluxoid formation in superconducting thin film rings.
abstract: 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.
authors.affiliation: IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Kirtley
authors.forename: C C
authors.initials: CC
authors.lastname: Tsuei
authors.forename: F
authors.initials: F
authors.lastname: Tafuri