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 intere sting aspect of these experiments is the possibility to observe and in vestigate different mechanisms of the superconductivity destruction de pending 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 o f d/xi(T) > 4.5 the destruction of superconductivity starts, as in bul k samples, with the formation of a normal shell along the outer surfac e of the cylindrical sample together with a layer of the two-dimension al mixed state at the inner surface. Investigations on films allowed f or the first time to measure the thickness of the two-dimensional mixe d state.