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Overwritable Double-Layered Magneto-Optic Disk Media

Published online by Cambridge University Press:  21 February 2011

Osamu Ishii  and
Iwao Hatakeyama
Osamu Ishii
Affiliation:
NTT Applied Electronics Laboratories, Tokai-mura, Ibaraki-ken 319-11. Japan
Iwao Hatakeyama
Affiliation:
NTT Applied Electronics Laboratories, Tokai-mura, Ibaraki-ken 319-11. Japan
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Abstract

An overwritable magneto-optic disk with a double-layered medium is described. The medium consists of magnetic recording (low coercivity, Hc, and high Curie temperature. Tc) and reproducing (high Hc and low Tc) layers. After a magnetic head writes data on a recording layer. a laser beam from an optical head irradiates a written track to heat a reproducing layer above its Tc. During cooling, the reproducing layer is magnetized by the flux from the bits on the recording layer with a width equal to that of the focused laser beam. These printed bits are read with the optical head. By repeating the above operations. the overwrite process is achieved. This overwrite mechanism is confirmed by using a Gd-Tb-Fe-Co (low Hc and high Tc)/ Tb-Fe (high Hc and low Tc) double-layered medium, a Winchester type magnetic head and an optical head. A wide gap magnetic head can write 1 μ m bits on the recording layer at a 0.52 μm flying height. Such wide spacing is promising for increased operational stability. Magnetic writing is of great advantage in increasing the recording density due to its rectangular bit shape.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 150: Symposium F – Materials for Magneto-Optic Data Storage , 1989 , 143
Copyright
Copyright © Materials Research Society 1989

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References

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