U.S. Philips Corporation

Friedrich J Den Broeder

Wouter Bastiaan Zeper

Mark Thomas Johnson

Freddy Roozeboom

Paul Van Der Sluis

Peter Francis Carcia

Hans Willem Van Kesteren

Peter Alexander Duine

Reiner Maria Jungblut

Cornelis Draijer

Johannes M Kerkhof

Henricus J Draaisma

Ralph M Hanzen

Willem F Godlieb

Franciscus J Greidanus

Jelto W Smits

Alexander Kahle

A description is given of an optical switching device (1) comprising a transparent substrate (3), a switching film (5) of a hydride compound of a trivalent transition or rare earth metal having a thickness of 300 nm, and a palladium capping layer (7) having a thickness of 30 nm. The capping layer is in contact with hydrogen. An electric current through the switching film (5) can be switched on and off between the terminals (9, 11). Joule heating of the switching film (5) causes a rapid transition from the transparent trihydride state to the absorbing dihydride state. By switching off the current, the switching film (5) cools down, which results in the formation of the absorbing dihydride state. The conversion between both states is reversible and can be repeated many times. The device can be used for controlling light beams, or it can be used in or for a display. Optionally, cooling of the switching film (5) is obtained with a Peltier element in thermal contact with the switching film (5).

Optical switching device

The addition of Os or Re to the Co layers of a magneto-optical recording medium comprising a Co/X multilayer, where X=Pt, Pd, Au, Ni or Ru, results in a reduction of both the Curie temperature and the magnetization. By virtue thereof, the rewritability of the medium is improved and higher write frequencies can be employed.

Magneto-optical recording medium

A device and method for controllably locally altering the magnetization direction in a body of magnetic material, whereby a layer of at least one of non-metallic material and a semi-metallic material is disposed on a surface of the body, on which layer is provided a body of magnetic material having a fixed magnetization direction, whereby both bodies of magnetic material are magnetically coupled across the interposed layer, the nature of this magnetic coupling being locally alterable by means of locally subjecting the layer to a controllable electric field.

Magnetic device and method for locally controllably altering

A record carrier for thermomagnetic recording of information and magneto-optical readout of the recorded information. The record carrier includes a substrate and a recording layer thereon in the form of multi-layers of magnetic and non-magnetic material, the magnetic layers predominately containing cobalt and the non-magnetic layers predominantly containing transition metal. The magnetic and non-magnetic layers alternate, and the overall thickness of the complete multi-layer recording layer is less than 75 nm. Such a recording layer achieves a significant improvement in both thermomagnetic write properties and magneto-optical read properties.

Record carrier for thermo-magnetic recording and magneto-optical readout

The invention provides a magnetic recording medium comprising a substrate of a nonmagnetic material bearing a thin magnetic layer with perpendicular anistropy. The magnetic thin layer comprises alternate layers of Pd and Co. The signal-to-noise ratio upon reading the stored information is considerably improved in that the thicknesses of the individual layers of Pd are between 0.2 and 2.0 nm and that the individual layers of Co consist of at least one monolayer of Co atoms and have thicknesses which are smaller than 0.3 nm. The thin magnet layer may be manufactured, for example, by electron beam vacuum vapor deposition of the individual layers of Pd and Co.

Magnetic recording medium

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Eindhoven, Netherlands

Friedrich J Den Broeder