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

Abstract

The critical current hysteresis of long Ag-Sn proximity-effect bridges, observed in the current-voltage characteristics obtained at helium bath temperatures T above and below the A point of helium T~, shows a jump discontinuity at T = TA. The relevance of the observed phenomenon to existing theories of superconductors driven into resistive states by direct currents is discussed.

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

“…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.…”

“…For example, in the study of the current-induced destruction of superconductivity in thinfilm superconductors several models 1,3,4,7 have been used to account for the experimentally observed critical current hysteresis, each having a limited range of validity, depending on the power levels involved and the heat transfer environment. 6 Similarly, some of the model predictions 9"14 in *Research carried out at the Tata Institute of Fundamental Research. nonequilibrium superconductivity have not been supported by adequate experimental evidence, because of such experimental factors 11 as the efficiency of phonon removal from the system (in other words, the heat transfer environment).…”

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