Epitaxial Film System of Superconducting Oxides
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
New superconducting oxide materials (based upon perovskite and K2NiF4 structures) composed of alkaline earths and copper with valence >2have been described by J. G. Bednorz and K. A. Mueller in Z . Phys. B64, 189 (1986). Reproducible and stable films for commercial devices can be made by depositing appropriate starting materials, such as Y1.4Ba0.6CuO4-, on a single crystal wafer substrate, such as YAlO3 . The latter has a perovskite-type structure. Upon being ground, polished and chemically-mechanically finished to produce a damage-free flat surface, this surface should be ideal for epitaxial film growth when the film composition is such that its atoms are arranged and spaced similarly to those below in the substrate. A lattice-matched film and substrate are preferred to material sets not coherently matched.