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Epitaxial Film System of Superconducting Oxides

IP.com Disclosure Number: IPCOM000034749D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Giess, EA: AUTHOR [+2]

Abstract

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.

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Epitaxial Film System of Superconducting Oxides

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. Rare earth ions can be substituted for Yttrium, and Ga3+ can be substituted for Al3+ in the substrate to adjust lattice constants in solid solutions. Similarly, film composition can be changed to match substrate characteristics, especially with regards to crystallographic lattice spacing. For example, Sr2+ or Ca2+ can be substituted for Ba2+ to decrease the lattice parameter, and Yb2+ would replace Y3+ .

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