Evaporation of high Tc Y-Ba-Cu-O superconducting thin film on Si and SiO2 with a zirconia buffer layer

This patent describes a process for producing a composite consisting essentially of substrate, a zirconium dioxide film and a superconductive film having a composition represented by the formula YBaxCuyOz where x ranges from about 1.7 to about 2.3, where y ranges from about 2.7 to about 3.3 and where z ranges from about 6.5 to about 7.0. The superconductive film having a zero resistance transition temperature of at least about 38 K. The process consists essentially of providing a silicon, oxidized elemental silicon, silicon dioxide and aluminum oxide, depositing a microscopically pore-free film ranging in thickness from about 2000 Angstroms to about 4000 Angstroms of zirconium dioxide on the substrate in a partial vacuum, heating the resulting film-carrying substrate in a partial vacuum to an annealing temperature ranging from about 450 degrees C. to about 850 degrees C, depositing by evaporation on the zirconium dioxide film Y, Ba, Cu and O in amounts required for the superconductive film. The heating being sufficient to produce the orthorhombic crystal structure in an amount sufficient to produce the superconductive film, and cooling the resulting structure in oxygen at about atmospheric pressure at a rate of less than about 5 degrees C. per minute which produces the superconductive film