Perpendicular magnetic recording medium and hard disk drive using the same
First Claim
1. A perpendicular magnetic recording medium comprising a substrate, a magnetic recording layer and a protective layer, whereinthe magnetic recording layer includes a perpendicular recording layer, a magnetic coupling layer and a writing assist layer;
- the perpendicular recording layer is a Co alloy layer containing an oxide disposed between the magnetic coupling layer and the substrate;
the magnetic coupling layer is a ferromagnetic layer disposed between the perpendicular recording layer and the writing assist layer;
the writing assist layer is a ferromagnetic layer disposed between the magnetic coupling layer and the protective layer;
the saturation magnetization of the magnetic coupling layer is lower than the saturation magnetization of the perpendicular recording layer or the writing assist layer; and
the thickness of the magnetic coupling layer is 1 nm or more and 3 nm or less.
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Abstract
Embodiments of the present invention provide a perpendicular magnetic recording medium having an improved writing property due to the exchange spring effect and capable of stable production. According to one embodiment, a perpendicular magnetic recording medium includes a non-magnetic substrate; an adhesion layer; a soft magnetic underlayer; a seed layer; and intermediate layer; a magnetic recording layer at least including a perpendicular recording layer, a writing assist layer, and a magnetic coupling layer disposed between the perpendicular recording layer and the writing assist layer; a protective layer, and a lubrication layer, in which the saturation magnetization of the magnetic coupling layer is lower than the saturation magnetization of the writing assist layer, the saturation magnetization of the magnetic coupling layer is 300 kA/m (300 emu/cc) or lower, and the thickness of the magnetic coupling layer is 1 nm or more and 3 nm or lower.
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Citations
23 Claims
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1. A perpendicular magnetic recording medium comprising a substrate, a magnetic recording layer and a protective layer, wherein
the magnetic recording layer includes a perpendicular recording layer, a magnetic coupling layer and a writing assist layer; -
the perpendicular recording layer is a Co alloy layer containing an oxide disposed between the magnetic coupling layer and the substrate; the magnetic coupling layer is a ferromagnetic layer disposed between the perpendicular recording layer and the writing assist layer; the writing assist layer is a ferromagnetic layer disposed between the magnetic coupling layer and the protective layer; the saturation magnetization of the magnetic coupling layer is lower than the saturation magnetization of the perpendicular recording layer or the writing assist layer; and the thickness of the magnetic coupling layer is 1 nm or more and 3 nm or less. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A perpendicular magnetic recording medium including a substrate, a magnetic recording layer, and a protective layer, wherein
the magnetic recording layer includes a perpendicular recording layer, a magnetic coupling layer, and a writing assist layer; -
the perpendicular recording layer is a Co alloy layer containing an oxide; the magnetic coupling layer is a ferromagnetic layer disposed between the perpendicular recording layer and the writing assist layer; the writing assist layer is a ferromagnetic layer comprising a Co alloy containing at least Cr and Pt, the magnetic coupling layer is an alloy comprising Co and Cr as a main ingredient with the Co content of 70 at % or more and 75 at % or less; and the thickness of the magnetic coupling layer is 1 nm or more and 3 nm or less. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A hard disk drive comprising:
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a magnetic head including a writing main pole, an auxiliary return pole, and a trailing shield; and a perpendicular recording medium including a substrate, a magnetic recording layer and a protective, the magnetic recording layer having a perpendicular recording layer, a magnetic coupling layer and a writing assist layer, wherein the perpendicular recording layer is a Co alloy layer containing an oxide; the magnetic coupling layer is a ferromagnetic layer disposed between the perpendicular recording layer and the writing assist layer; the writing assist layer is a ferromagnetic layer comprising a Co alloy containing at least Cr and Pt; the saturation magnetization of the magnetic coupling layer is lower than the saturation magnetization of the perpendicular recording layer or the writing assist layer; and the thickness of the magnetic coupling layer is 1 nm or more and 3 nm or less. - View Dependent Claims (21, 22, 23)
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16. A hard disk drive comprising:
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2 a magnetic head including a writing main pole, an auxiliary return pole, and a trailing shield; and a perpendicular recording medium including a substrate, a magnetic recording layer and a protective, the magnetic recording layer having a perpendicular recording layer, a magnetic coupling layer and a writing assist layer, wherein the perpendicular recording layer is a Co alloy layer containing an oxide disposed between the magnetic coupling layer and the substrate; the magnetic coupling layer is a ferromagnetic layer disposed between the perpendicular recording layer and the writing assist layer; the writing assist layer is a ferromagnetic layer disposed between the magnetic coupling layer and the protective layer; the magnetic coupling layer is an alloy comprising Co and Cr as a main ingredient with the content of Co of about 70 at % or more and 75 at % or less; and the thickness of the magnetic coupling layer is 1 nm or more and 3 nm or less. - View Dependent Claims (17, 18, 19, 20)
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Specification