Johnson Matthey Public Limited Company

Johnson Matthey Electronics, Inc.

Derek P Pearson

Joseph Miller

Philip G Pitcher

Duncan Roy Coupland

Philip George Pitcher

A materials system in which exchange coupling is achievable has the potential for allowing direct overwriting of data and comprises at least two multilayer films of platinum and cobalt with independently controlled coercivity and Curie temperatures.

Platinum and cobalt multilayer recording materials system and process

Pt/Co multilayer materials systems having a thin metal interlayer possess superior room temperature coercivity, a square polar Kerr hysteresis loop, sufficient polar Kerr rotation, and are suitable for magneto-optical recording. These material systems allow the reading and writing of information from the substrate side of the multilayer film.

Multilayer film materials system

Pt/Co multilayer systems having a thin metal interlayer possess superior room temperature coercivity, a square polar Kerr hysteresis loop, sufficient polar Kerr rotation, and are suitable for magneto-optical recording. These materials systems allow the reading and writing of information from the substrate side of the multilayer film.

Magneto-optical recording materials system

Nickel alloys comprising less than 25% by volume of .gamma.' precipitate and containing 23 to 37% by weight of chromium and in addition a trace to 1.7% carbon, 0.3 to 4% by weight of platinum and/or 0.3 to 8% by weight of ruthenium, a trace to 1.5% by weight titanium and/or a trace to 1.5% aluminium the balance being nickel. The alloys combine improved corrosion resistance with high mechanical strength. Major improvements in mechanical strength seem to be obtained by adding small amounts of titanium and/or aluminium. The alloy is especially suited for use in contact with molten glass for example in a centrifugal spinner.

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Reading, United Kingdom

Derek P Pearson