Critical Currents in Thin Planar Films

Abstract

Plane rectangular films of superconducting Sn, which are thin compared to the 0 deg K penetration depth, were prepared. The currents and current densities necessary to restore the normal state in these films were measured as a function of temperature. The critical current density was found to vary as (1 - t/sup 2/)/sup 2/3/, in agreement with theory. The measurements indicate a 0 deg K critical current density on the order of 20 MA/cm/sup 2/, also in qualitative agreement with theory. (T.F.H.)