Observation of Magnetic Flux Generated Spontaneously During a Rapid Quench of Superconducting Films

TL;DR

This study observes spontaneous magnetic flux formation in superconducting films during rapid cooling, supporting the Kibble-Zurek mechanism's prediction of topological defect creation during phase transitions.

Contribution

First experimental evidence of magnetic flux generation during rapid quench of superconducting films at extremely high cooling rates, confirming theoretical predictions.

Findings

Flux formation increases with cooling rate

Flux patterns are consistent with topological defect creation

Supports Kibble-Zurek mechanism in superconductors

Abstract

We report observations of spontaneous formation of magnetic flux lines during a rapid quench of YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ films through T$_{c}$. This effect is predicted according to the Kibble-Zurek mechanism of creation of topological defects of the order parameter during a symmetry-breaking phase transition. Our previous experiment, at a quench rate of 20K/sec, gave null results. In the present experiment, the quench rate was increased to \TEXTsymbol{>} 10$^{8}$ K/sec. Within experimental resolution, the dependence of the measured flux on the cooling rate is consistent with the prediction.