Observation of Thermal Fluctuations in Superconducting Microbridges

Abstract
Thermal fluctuations of the type described by Langer and Ambegaokar and by McCumber and Halperin have been observed in superconducting thin-film rings containing microbridge sections. A peak in the fluctuation rate was found near the transition temperature. The temperature dependence of the observed rates is in agreement with the McCumber-Halperin fluctuation-rate equations and the deduced parameters are consistent with the theory.