Stimulation of superconductivity by microwave radiation in wide tin films (Review Article)

Abstract

The review is devoted to an experimental study of simulation of superconductivity by microwave radiation in superconducting films. An influence of the power, frequency of microwave radiation, as well as temperature and width of superconducting films on behavior of experimental dependencies of stimulated the critical current and the current at which a vortex structure of the resistive state vanishes and the phase-slip first line appears is analyzed. The experimental studies of films with different width reveal that the effect of superconductivity stimulation by microwave field is common and occurs in both the case of uniform (narrow films) and non-uniform (wide films) distribution of superconducting current over the film width. It is shown that stimulation of superconductivity in a wide film increases not only the critical current and the critical temperature, but also the maximum current at which there is a vortex state in the film. The effect of superconductivity stimulation by microwave radiation in wide films can be described by the Eliashberg theory, which was used to explain the same phenomenon in narrow channels. For the first time it was found experimentally that when the film width increases, the range of radiation power, at which the effect of superconductivity stimulation is observed, shrinks abruptly, and hence the probability of its detection decreases.