Investigation of the sources of asymmetry effects in the velocity of destruction of superconductivity by current in Type II Ta wires

The phenomenological theories for the velocity of destruction of superconductivity by current can be improved by taking into account the temperature dependences of the thermal conductivities K/sub N/(T), K/sub S/(T) and the specific heats C/sub N/(T), C/sub S/(T). In earlier works these quantities were usually evaluated at temperature T/sub t/, that of the center of the propagating normal(N)--superconducting(S) interface. It was found that the asymmetry in v observed in ''dirty'' type-II Ta wires could be tentatively explained by K/sub N/(I greater than I/sub i/; parallel case) greater than K/sub N/(I = 0) and K/SSUG N/(I greater than I/sub i/; antiparallel case) less than K/sub N/(I = 0) and propagating interface specific anomaly parameter A(parallel) greater than A(antiparallel) and the width of the propagating interface = 2n' xi(T) with n' = 10, where I/sub i/ is the current at the superconducting--mixed interface. (2 figures) (U.S.)