1. A superconducting film comprising: a non-equilibrium structure providing local variations in superconducting transition temperature, said structure formed from at least two components, at least one of said components being a metallic material and at least one of said components being a non-metallic material, said structure including a plurality of regions exhibiting characteristic lengths in at least two directions through the structure of less than 500 Angstroms to provide AC to DC conversion of an RF AC signal imposed on the structure in the absence of a magnetic field applied thereto, said structure having an oxygen content throughout the structure of less than ten percent, said structure includes a microscopically inhomogeneous microstructure providing said characteristic length and said microstructure being a columnar microstructure.