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Search for Spontaneous Nucleation of Magnetic Flux During Rapid Cooling of YBCO films Through Tc

Raz Carmi·Emil Polturak
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Abstract

We describe an experimental search for spontaneous formation of flux lines during a rapid quench of thin YBaCuO films through Tc. This effect is expected according to the Kibble-Zurek mechanism of a creation of topological defects of the order parameter during a symmetry breaking phase transition. Spontaneously formed vortices were previously observed in superfluid 3He, while a similar experiment in superfluid 4He gave negative results. Using a high Tc SQUID, we measured both the magnetic flux in the sample during a quench with a sensitivity of 20 phi-0/cm^2, and the field noise which one would expect from flux lines pinned in the film. The sensitivity was sufficient to detect spontaneous flux at a level corresponding to 10^(-3) of the prediction. Within our resolution, we saw no evidence for this effect.

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Raz Carmi, Emil Polturak. 1999-08-17. Search for Spontaneous Nucleation of Magnetic Flux During Rapid Cooling of YBCO films Through Tc. https://doi.org/10.1103/physrevb.60.7595

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