Dynamic pinning model of electrical dissipation in the superconducting surface sheath

The dynamic pinning model of Yamafuji and Irie is adapted to the problem of electrical dissipation in the superconductive surface sheath. The free energy of the surface flux-spot lattice and its shear modulus—quantities required by the model—are calculated. The dc current-voltage characteristics of thick, Pb-In alloy films are analyzed in terms of an excess currentI_pdue to pinning. The observed dependence ofI_pupon magnetic field is in good accord with the predictions of the model; the variations with temperature and alloy composition are made plausible as well.Work supported in part by Research Corporation.