Process of forming a high temperature superconductor on a metal substrate surface

Claim 1

A process of forming on a surface of a substrate a superconductive crystalline mixed metal oxide thin film exhibiting superconductivity at a temperature in excess of 85° K. and containing a crystalline superconductive phase exhibiting a 37 Å crystal cell c-axis by the steps of forming a precursor of the superconductive thin film on the substrate surface containing bismuth, lead, copper and a combination of the alkaline earths A and calcium, where A is strontium and 0 to 10 percent barium, based on strontium and barium combined in the proportions required to form the 37 Å crystal cell c-axis superconductive phase and thermally converting the thin film precursor to the superconductive thin film, characterized in that the substrate surface is comprised of at least one of silver, gold or a platinum group metal, at least 0.7 atom of lead for each four atoms of the alkaline earths is in the thin film precursor to enhance formation of the 37 Å crystal cell c-axis superconductive phase on the substrate support surface, and at least two atoms of bismuth are maintained in the thin film precursor for each four atoms of the alkaline earths.