The resistive states of wide superconducting films caused by dc and ac currents

The review is devoted to the research of resistive state in wide superconducting films due to direct and alternating currents in the absence of an external magnetic field. It has been found experimentally that the IV-characteristics and their parameters are well described by the Aslamazov–Lempitsky theory of resistive vortex state in the range of existence of the film vortex state, which has long been lacking a reliable support. There is experimental evidence that the vortex current resistivity mechanism is absent at currents greater than the maximum current of the existence of the resistive vortex state in wide films. The nonvortex nature of phase slip lines (PSL) in wide films is proved experimentally. It is shown that phase-slip lines arise in a wide superconducting film irradiated with an external microwave field whose power exceeds the critical value. The resistance of these phase slip lines depends on irradiation frequency. The PSL results obtained in wide films are similar to the phase slip centers ones taken in narrow channels, suggesting the identical nature of the phase-slip processes in these two objects. It is found that the current resistive state of a wide film is due to two alternative mechanisms that occur one after the other. These are a penetration of the Pearl vortices of magnetic field of current into the film and their motion across it, and the emergence of phase-slip lines of the superconducting order parameter. PACS: 74.25.Sv Critical currents; 74.25.Dw Superconductivity phase diagrams; 74.40.Gh Nonequilibrium superconductivity. © 2014 Institute for Low Temperature Physics and Engineering. All rights reserved.