Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

New high density magnetic recording tapes

With the coming advent of high definition television, the current generation of video tapes will have to be replaced by higher performance tapes, capable of handling the increased data flow per time unit. This will require a bit size of 1 to 2 square micrometres, several times smaller than the 6 square micrometres achieved by a state of the art metal particle (MP) tape. We studied 2 metal alloys of possible use:
obliquely deposited cobalt nickel oxide, whose intrinsic magnetic direction is adapted to the field distribution of a conventional video head;
cobalt chromium with the magnetization perpendicular to the film plane, which provides the highest recording densities when used with a so called single pole head.

The polyester substrates were investigated and optimized, followed by the development of functional tapes based on the evaporation or the sputtering of cobalt nickel oxide and cobalt chromium layers. In addition, a comprehensive study of the magnetic properties of metallic thin films was carried out and available surface treatment have been analyzed and rated. Laboratory prototypes of the promised types of metal evaporated (ME) tapes exist now. Bit sizes below 2 square micrometres have been reached, with still frame times of several hours. For the cobalt chromium tape, a bit size of 1 square micrometre has been achieved with a sputtered layer of cobalt-79 chromium-21, using a substrate covered with a germanium underlayer at a temperature of 200 C.


Marianne KOENIG
Tel.: +35-2-36665639
Fax: +35-2-36665005
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