CURRENT-INDUCED RESISTIVE STATE OF SUPERCONDUCTING TIN WHISKERS WITH INDIUM IMPURITIES

We have investigated the current-induced step-like structure in the V-T and V-I characteristics of tin whiskers with a mean free path l for the electrons which is reduced by indium impurities (up to 3.6 at %). The extrapolation of the V-I characteristics beyond the first voltage step shows a zero-voltage intercept I0≈0.5 Ic (Ic=critical current). From the differential resistance beyond the first voltage step a length LAn1 can be obtained which is proportional to l1/2. These results can be understood by assuming phase-slip centers in the whisker which carry a time-averaged supercurrent of approximately 0.5 Ic above the critical current, and at which a voltage is developed by the healing" of nonequilibrium quasiparticles. © 1979 Springer-Verlag."