Anti-ferromagnetically coupled granular-continuous magnetic recording media
First Claim
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1. An anti-ferromagnetically coupled, granular-continuous (“
- AFC-GC”
) magnetic recording medium, comprising a layer stack formed on a surface of a non-magnetic substrate and including;
(a) a continuous ferromagnetic stabilizing layer;
(b) a non-magnetic spacer layer contacting said ferromagnetic stabilizing layer; and
(c) a granular ferromagnetic layer contacting said non-magnetic spacer layer, said granular ferromagnetic layer comprises a CoCrPt—
X′
material, where X′
is selected from the group consisting of;
oxides, nitrides, and carbides, and adjacent magnetic grains are substantially magnetically isolated from each other;
wherein;
(i) said continuous ferromagnetic stabilizing layer and said granular ferromagnetic layer are anti-ferromagnetically coupled across said non-magnetic spacer layer, the amount of anti-ferromagnetic coupling preselected to ensure magnetic relaxation after writing;
(ii) lateral interactions in said granular, ferromagnetic recording layer are substantially completely eliminated or suppressed; and
(iii) the exchange coupling strength in said continuous, ferromagnetic stabilizing layer is preselected to be larger than the strength of the anti-ferromagnetic coupling provided by the non-magnetic spacer layer to thereby enhance thermal stability of the recording bits.
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Abstract
An anti-ferromagnetically coupled, granular-continuous (“AFC-GC”) magnetic recording medium having increased thermal stability, writability, and signal-to-medium noise ratio (“SMNR”), comprising a layer stack including, in sequence from a surface of a non-magnetic substrate:
- (a) a continuous ferromagnetic stabilizing layer;
- (b) a non-magnetic spacer layer; and
- (c) a granular ferromagnetic recording layer;
- wherein:
- (i) the continuous ferromagnetic stabilizing and granular ferromagnetic recording layers are anti-ferromagnetically coupled across the non-magnetic spacer layer, the amount of anti-ferromagnetic coupling preselected to ensure magnetic relaxation after writing;
- (ii) lateral interactions in the granular, ferromagnetic recording layer are substantially completely eliminated or suppressed; and
- (iii) the exchange coupling strength in the continuous, ferromagnetic stabilizing layer is preselected to be slightly larger than the strength of the anti-ferromagnetic coupling provided by the non-magnetic spacer layer to thereby enhance thermal stability of the recording bits.
60 Citations
24 Claims
-
1. An anti-ferromagnetically coupled, granular-continuous (“
- AFC-GC”
) magnetic recording medium, comprising a layer stack formed on a surface of a non-magnetic substrate and including;(a) a continuous ferromagnetic stabilizing layer; (b) a non-magnetic spacer layer contacting said ferromagnetic stabilizing layer; and (c) a granular ferromagnetic layer contacting said non-magnetic spacer layer, said granular ferromagnetic layer comprises a CoCrPt—
X′
material, where X′
is selected from the group consisting of;
oxides, nitrides, and carbides, and adjacent magnetic grains are substantially magnetically isolated from each other;
wherein;(i) said continuous ferromagnetic stabilizing layer and said granular ferromagnetic layer are anti-ferromagnetically coupled across said non-magnetic spacer layer, the amount of anti-ferromagnetic coupling preselected to ensure magnetic relaxation after writing; (ii) lateral interactions in said granular, ferromagnetic recording layer are substantially completely eliminated or suppressed; and (iii) the exchange coupling strength in said continuous, ferromagnetic stabilizing layer is preselected to be larger than the strength of the anti-ferromagnetic coupling provided by the non-magnetic spacer layer to thereby enhance thermal stability of the recording bits. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
- AFC-GC”
Specification