Metastable states of superconducting indium films

A new technique (division of the film into very many small squares) allows the observation of supercooling and superheating of superconducting layers under both parallel and perpendicular fields. The possible existence of ''edge'' nucleation in thick films, analogous to surface nucleation for semiinfinite samples, is shown. The superconducting parameters determined for films extrapolate correctly to known bulk values. Critical thicknesses for passage from type I to type II behavior agree with theoretical predicitions. Nonlocal corrections to the penetration depth allow one to explain deviations from the Gorkov--Goodman relation for bulk metals