Viscous flow of vortices in ideal type-II amorphous superconductors

Low-field flux-flow resistivity in ideal type-II amorphous bulk superconductors ${\mathrm{Zr}}_3$Ni and ${\mathrm{Zr}}_3$Rh in both as-quenched and annealed states has been studied. The results provide the first experimental evidence that it is necessary to include all the energy-dissipation terms arising from normal current in the vortex cores (Bardeen-Stephen mechanism), relaxation of the order parameter (Tinhkam mechanism), and as well the slow diffusion mechanism of relaxation of the order parameter caused by the anomalous term in the time-dependent microscopic theory (Gor'kov-Kopnin mechanism) in the viscosity coefficient at low field. The last term is absent in "clean" alloys.