Critical-current hysteresis of superconducting proximity-effect bridges under phonon injection

Abstract

A dc electric current is injected through the transverse normal-metal strip of Ag-Sn proximity-effect bridges to generate phonons which propagate through and further weaken the superconductivity in the proximity-effect-induced weak region by creating quasiparticles (by pair-breaking mechanisms}. Consequently a decrease of the critical-current hysteresis is observed in the current-voltage characteristics of these bridges. These results cannot be adequately accounted for by simple heating. Further, we find that Parker's modified heating theory of nonequilibrium superconductors has to be invoked for a qualitative understanding of the observed phenomena.

Study of phonon-injection-induced destruction of superconductivity in tin films

“…The experimental I-V characteristics of the superconducting thin-film strip for various injection currents Ij through the silver strip were obtained using the same procedure as in Refs. 15 …”

“…This part of the I-V characteristic has been extensively investigated and discussed elsewhere. 6,15 The salient features of the rest of the I-V characteristics can be easily understood on the basis of the well-known hotspot model of Skocpol et al I (SBT). The dc 1-V characteristics of superconducting thin-film microbridges at low bath temperatures have been satisfactorily accounted for by this simple model of a localized normal hotspot maintained by Joule heating.…”

“…In the past few years there has been considerable interest in the equilibrium and nonequilibrium properties of thin-film superconductors in [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] their current-carrying states as well as voltage-sustaining states. However, some of the experimental observations remain without an adequate theoretical explanation and in some cases some of the model predictions remain without adequate experimental support.…”

“…9 [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] decisive role in all the above mvesugauons.…”

Anomalous hysteresis of the critical current in long proximity-effect bridges

“…Combining Eqs. (1), (2), and (5), we can write the expression for the critical current hysteresis ~ (t) as…”