Transient Response of Superconducting Indium Microbridges to Supercritical Current Pulses

Superconducting sampling circuits have been used to investigate the transient response of long indium microbridges to current pulses in excess of their critical currents. For the first time, the rising-edge kinetic inductance spike and the nonzero minimum voltage have been observed, as well as the delay time until the normal state appears. These results are in reasonable agreement with a detailed theoretical model of the experiment and yield an estimate of 140 ps for ${\tau }_E$, the inelastic scattering time, in indium.