Magnetic recording medium with multiple exchange coupling layers and small grain magnetic layers
AssigneeWestern Digital Technologies, Inc.
InventorYoshihiro Ikeda
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Abstract
A magnetic recording medium is provided that includes a recording layer structure including a first magnetic recording layer, a second magnetic recording layer, a third magnetic recording layer, a fourth magnetic recording layer, and a plurality of nonmagnetic exchange coupling layers. The first magnetic recording layer is closest to a substrate and the fourth magnetic recording layer is farthest from the substrate. An amount of Co in the first magnetic recording layer is greater than or equal to the amount of Co in the second magnetic recording layer, the third magnetic recording layer, and the fourth magnetic recording layer.
Claims20
A magnetic recording medium comprising:
- a recording layer structure comprising:
- a first magnetic recording layer;
- a second magnetic recording layer;
- a third magnetic recording layer;
- a fourth magnetic recording layer;
- and
- a plurality of nonmagnetic exchange coupling layers,
- wherein the first magnetic recording layer is closest to a substrate and the fourth magnetic recording layer is farthest from the substrate;
- and
- wherein an amount of Co in the first magnetic recording layer is greater than or equal to the amount of Co in the second magnetic recording layer, the third magnetic recording layer, and the fourth magnetic recording layer.
A magnetic recording medium comprising:
- a recording layer structure comprising:
- a plurality of magnetic recording layers;
- and
- a plurality of nonmagnetic exchange coupling layers alternating with the plurality of magnetic recording layers;
- wherein each of the plurality of nonmagnetic exchange coupling layers comprises Co in an amount that is less than an amount of Co in each of the plurality of magnetic recording layers.
A magnetic recording medium comprising:
- a recording layer structure comprising:
- a first magnetic recording layer;
- a second magnetic recording layer disposed above the first magnetic recording layer;
- a third magnetic recording layer disposed above the second magnetic recording layer;
- a fourth magnetic recording layer disposed above the third magnetic recording layer;
- and
- a plurality of nonmagnetic exchange coupling layers,
- wherein:
- an amount of Co in the first magnetic recording layer is greater than or equal to the amount of Co in the second magnetic recording layer, the third magnetic recording layer, and the fourth magnetic recording layer;
- and
- a magnetic anisotropy energy of each of the first magnetic recording layer and the fourth magnetic recording layer is greater than a magnetic anisotropy energy of each of the second magnetic recording layer and the third magnetic recording layer.
Dependencies are inferred from the claim text.