International Business Machines Corporation

Leland Stanford Junior University

Roger W Barton

Kurt A Rubin

Grace Lim Gorman

Hans J Coufal

Wen Yaung Lee

Kookrin Char

Aharon Kapitulnik

Robert H Hammond

Mark Lee

Victor B Jipson

Martin Y Chen

Vincent Marrello

Stephen S Laderman

Charles Raymond Davis

Ann F Marshall

Novel superconducting oxide compositions of the formulas (YBa.sub.2 Cu.sub.3.25).sub.a O.sub.z and Y.sub.2 Ba.sub.4 Cu.sub.8 O.sub.20-x (248) are provided which can have an ordered defect structure stacked on one axis. Mi

High-temperature superconductors

An optical storage system has an information containing film of a material which has a crystallization temperature between 100.degree. C. and 400.degree. C. and can be switched between the amorphous and the crystalline states. Both the amorphous and crystalline states are substantially a single phase where the stoichiometric ratio of the material remains unchanged. Spots on the film is heated with a circular laser beam with a controlled pulse duration and intensity to melt the material in the spots. The spots are quenched at one rate to produce the amorphous state, and in a second revolution of the disk, at a different rate to produce the crystalline state.

Process for optically storing information using materials having a

A method of and structure for optical recording by energy-induced homogenization or fractionation is disclosed. When the method involves fractionation, a film is provided that contains a homogeneous mixture of a matrix material and an incident energy absorbing material. A spot on the film is treated with sufficient energy in the form of electric fields, radiation or heat, or combinations thereof to effect fractionation and/or homogenization of the film which will undergo further physical state transition only under treatment with additional energy. In a preferred embodiment, the fractionation is effected by laser radiation. The laser irradiated spot becomes inhomogeneous and can be detected by the resulting changes in its optical properties. When the method involves homogenization, a film is provided that contains a inhomogeneous mixture. The energy treated spot in this case becomes homogeneous without undergoing a phase transition between the amorphous and crystalline phases. Numerous combinations of fractionation and homogenization can result in the writing and erasing of information in a storage device.

Optical recording by energy-induced fractionation and homogenization

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Menlo Park, CA, United States of America

Roger W Barton