Dependence of the differential (''flux-flow'') resistance on critical current with allowance for superheating of samples

Current-voltage characteristics of cold-worked ribbon specimens of the Nb-(76--80%)Zr superconducting alloys were measured at various temperatures, various magnetic field intensities, and various orientations of the magnetic field relative to the plane of a specimen. The critical current was varied through more than one order of magnitude. The current-voltage characteristics were then calculated for various angles between the magnetic field and the plane of a specimen, with overheating of a specimen at the center taken into account and on the basis of the hypothesis that the differential resistance does not depend on the critical current. The close agreement between calculated and measured current-voltage characteristics validates this hypothesis (with the maximum pinning force equal to 5 x 10/sup 7/ dyn/cm/sup 3/ at T = 1.85 /sup 0/K). The problem of the stability of the resistive state having to do with heat transfer to the liquid helium is considered.