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INTERFACIAL La-Ba-Cu-O TYPE SUPERCONDUCTING THIN FILMS

IP.com Disclosure Number: IPCOM000035094D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Gallagher, WJ: AUTHOR [+2]

Abstract

The La-Ba-Cu-O type superconductors discovered by Bednorz and Muller are made up of planes of CuO6 octahedra sharing corners with the CuO6 planes separated by (La,Ba)-O layers within which the La and Sr are nine-fold coordinated to oxygen. The Cu-O bonding is very distorted, with the Cu assuming a planar four-fold coordination with oxygen. Substitution of Ba (or Sr) for La in small amounts oxidizes some of the Cu to Cu3+ and results in a mixed valence compound and modifies the superconducting transition temperature.

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INTERFACIAL La-Ba-Cu-O TYPE SUPERCONDUCTING THIN FILMS

The La-Ba-Cu-O type superconductors discovered by Bednorz and Muller are made up of planes of CuO6 octahedra sharing corners with the CuO6 planes separated by (La,Ba)-O layers within which the La and Sr are nine-fold coordinated to oxygen. The Cu-O bonding is very distorted, with the Cu assuming a planar four-fold coordination with oxygen. Substitution of Ba (or Sr) for La in small amounts oxidizes some of the Cu to Cu3+ and results in a mixed valence compound and modifies the superconducting transition temperature.

A unique structure in which superconductivity is observed only within an interfacial region is described. The two oxide layers, CuO6 and (La,Ba)-O, are deposited separately. For example, the (La,Ba)-O layer is deposited and annealed at an elevated temperature. Then the Cu-O layer is deposited and annealed. The time and temperature of anneal will determine the extent of the interdiffusion of the layers and the resulting width of this interfacial layer. Ultrathin layers as well as thicker layers are possible. The approach is also extendable to multilayers and to other superconducting oxide systems.

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