Transient response of a nonequilibrium superconductor to pulsed injection of quasiparticles through a tunnel barrier
We report the first direct measurements on the transient response of a nonequilibrium superconductor to high tunnel-current pulses. The sample is a Sn-I-Sn-I-Sn double-tunnel junction and the observed transient time is 20--30 nsec, depending on the samples. The calculated results based on the nonlinear Rothwarf--Taylor equation give a good fit to the experimental data for a reasonable set of parameter values. For injection strong enough to drive a film into the inhomogeneous gap state, the contribution of the negative diffusive term becomes important, suggesting the occurrence of an effective abnormal diffusion of quasiparticles. Measurements are also performed for the transient detector I--V characteristics at a certain sampling-gate delay time. It is shown that the inhomogeneous gap state is formed within a few tens of nanoseconds for bath temperatures both below and above T/sub lambda/.
- Research Organization:
- Institute of Materials Science, University of Tsukuba, Sakura-mura, Ibaraki, Japan
- OSTI ID:
- 5538205
- Journal Information:
- J. Low Temp. Phys.; (United States), Vol. 52:3
- Country of Publication:
- United States
- Language:
- English
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