Current-Induced Resistive State in Cylindrical Superconducting Films .2. 2-Dimensional Mixed-State of Type-1 Superconductors

We present an experimental study of the current induced destruction of superconductivity in films of type-1 superconductors. The most interesting aspect of these experiments is the possibility to observe and investigate different mechanisms of the superconductivity destruction depending on the ratio of the sample thickness d to the coherence length xi(T). If d/xi(T) < 4.5 we observe, above a critical current value, a resistive state throughout the section of the film, but in the case of d/xi(T) > 4.5 the destruction of superconductivity starts, as in bulk samples, with the formation of a normal shell along the outer surface of the cylindrical sample together with a layer of the two-dimensional mixed state at the inner surface. Investigations on films allowed for the first time to measure the thickness of the two-dimensional mixed state.