We report on the experimental verification of the Zurek-Kibble scenario in an isolated superconducting ring over a wide parameter range. The probability of creating a single flux quantum spontaneously during the fast normal-superconducting phase transition of a wide Nb loop clearly follows a scaling relation on the quenching time tau(Q), as one would expect if the transition took place as fast as causality permits. However, the observed Zurek-Kibble scaling exponent sigma=0.62 +/- 0.15 is two times larger than anticipated for large loops. Assuming Gaussian winding number densities we show that this doubling is well founded for small annuli.
Spontaneous fluxoid formation in superconducting loops
R MONACO;
2009
Abstract
We report on the experimental verification of the Zurek-Kibble scenario in an isolated superconducting ring over a wide parameter range. The probability of creating a single flux quantum spontaneously during the fast normal-superconducting phase transition of a wide Nb loop clearly follows a scaling relation on the quenching time tau(Q), as one would expect if the transition took place as fast as causality permits. However, the observed Zurek-Kibble scaling exponent sigma=0.62 +/- 0.15 is two times larger than anticipated for large loops. Assuming Gaussian winding number densities we show that this doubling is well founded for small annuli.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
