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Amorphous ZrO2-Al2O3 Oxide for Dielectric and Passivation Layers in Magneto-optic Recording Media

IP.com Disclosure Number: IPCOM000122340D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Related People

Lin, CJ: AUTHOR

Abstract

Disclosed is a ZrO2-Al2O3 oxide that has a stable amorphous structure and is consequently demonstrated as a good dielectric layer for protecting the active layer, e.g., rare-earth transition metal (RE-TM) alloy, of magneto-optic media against harmful molecules in the environment. In addition, this oxide has a large enough index of refraction, 2.04, to be useful in optically enhanced media structures.

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Amorphous ZrO2-Al2O3 Oxide for Dielectric and Passivation Layers
in Magneto-optic Recording Media

      Disclosed is a ZrO2-Al2O3 oxide that has a stable amorphous
structure and is consequently demonstrated as a good dielectric layer
for protecting the active layer, e.g., rare-earth transition metal
(RE-TM) alloy, of magneto-optic media against harmful molecules in
the environment.  In addition, this oxide has a large enough index of
refraction, 2.04, to be useful in optically enhanced media
structures.

      ZrO2 is chemically stable enough to be a good dielectric
material for passivating the RE-TM alloy layer. However, its
effectiveness of passivation is weakened by the fact that the
as-deposited ZrO2 film is either polycrystalline or amorphous with a
crystallization temperature of only 100~C, since it is well known
that grain boundaries provide fast diffusion paths; in this case, for
molecules harmful to the magneto-optic layer.  Since diffusivity in
the amorphous structure is much smaller than that along the grain
boundary, a stable amorphous modified ZrO2 is desirable to better
protect the magneto-optic layer. Moreover, the possibility of noise
due to crystallinity of the dielectric layer could be eliminated.
Stable amorphous ZrO2-based oxides are obtained by doping ZrO2 with
Al2O3, which is also chemically stable enough to passivate the RE-TM
alloy layers.  For example, an oxide of 76.8% ZrO2 + 23.2% Al2O3, in
molecular percentage, with an index of refract...