Showa Denko K.k.

Resonac Corporation

Japan Atomic Energy Agency

Kota Hasegawa

Haruhisa Ohashi

Katsuaki To

Takayuki Fukushima

Eishin Yamakawa

Ken Inoue

Takahiro Ukai

Yu Azuma

Shiro Entani

Seiji Sakai

A magnetic recording medium includes a non-magnetic substrate; a soft magnetic layer; a first seed layer; a second seed layer; an underlayer; and a perpendicular magnetic recording layer. The soft magnetic layer, the first seed layer, the second seed layer, the underlayer and the perpendicular magnetic recording layer are disposed on the non-magnetic substrate in this order. The first seed layer includes MoS, hexagonal-BN, WS, WSeor graphite. The second seed layer includes AlN having a hexagonal wurtzite type crystal structure. The underlayer includes Ru.

Magnetic recording medium, method of manufacturing same, and magnetic recording and reproducing apparatus

A magnetic recording medium includes a substrate, an underlayer disposed above the substrate, and a first magnetic layer disposed above the underlayer. The first magnetic layer has a granular structure including magnetic grains having a L1structure, and grain boundaries. A content of the grain boundaries is in a range of 25 volume percent to 50 volume percent, and the grain boundaries include a chalcogenide-based layered material.

Magnetic recording medium and magnetic storage apparatus

A magnetic recording medium includes a nonmagnetic substrate, a soft magnetic underlayer, an orientation control layer, a perpendicular magnetic layer, and a protection layer that are arranged in this order. The perpendicular magnetic layer includes a first magnetic layer and a second magnetic layer that are arranged in this order on the orientation control layer. The first magnetic layer has a granular structure including an oxide at grain boundary parts of magnetic grains, and the second magnetic layer is closest to the protection layer among layers within the perpendicular magnetic layer, and includes magnetic grains made of a CoCrPt alloy, and a nitride of carbon or a hydride of carbon.

Magnetic recording medium having magnetic layer with nitride of carbon or hydride of carbon, and magnetic storage apparatus

Magnetic recording medium having magnetic layer with hydride of carbon, and magnetic storage apparatus

A magnetic recording medium includes a non-magnetic substrate, a soft magnetic underlayer, an orientation control layer, a perpendicular magnetic layer, and a protective layer arranged in this order. The perpendicular magnetic layer includes a first magnetic layer and a second magnetic layer from the non-magnetic substrate side in this order. The second magnetic layer contains a magnetic grain and provided farthest from the non-magnetic substrate. The first magnetic layer has a granular structure that contains an oxide in a grain boundary. The second magnetic layer has a granular structure that contains a nitride of an element contained in the magnetic grain in a grain boundary.

Magnetic recording medium with nitride segregant, method for manufacturing same and magnetic recording and reproducing apparatus

A magnetic recording medium includes a non-magnetic substrate, a soft magnetic underlayer, an orientation control layer, a perpendicular magnetic layer, and a protective layer arranged in this order. The perpendicular magnetic layer includes a first magnetic layer and a second magnetic layer from the non-magnetic substrate side in this order. The second magnetic layer contains a magnetic grain and provided farthest from the non-magnetic substrate. The first magnetic layer has a granular structure that contains an oxide in a grain boundary. The second magnetic layer has a granular structure that contains a carbide of an element contained in the magnetic grain in a grain boundary.

Magnetic recording medium, with carbide segregant, method for manufacturing same and magnetic recording and reproducing apparatus

A magnetic recording medium includes a non-magnetic substrate on which at least a soft magnetic underlayer, an orientation control layer, a perpendicular magnetic layer, and a protective layer are disposed. The perpendicular magnetic layer includes first to fourth magnetic layers. A first exchange coupling control layer is disposed between the first magnetic layer and the second magnetic layer. A second exchange coupling control layer is disposed between the second magnetic layer and the third magnetic layer. Following relations are satisfied where Kuis a magnetic anisotropic constant of an i-th magnetic layer, Msis a saturation magnetization of the i-th magnetic layer, and tis a film thickness of the i-th magnetic layer, Ku&#x3e;Ku, Ku&#x3e;Ku, Ms&#xd7;t&#x3e;Ms&#xd7;t, Ms&#xd7;t&#x3e;Ms&#xd7;t, Ku&#x3c;Ku, and Ms&#xd7;t&#x3c;Ms&#xd7;t.

Magnetic recording medium and magnetic recording and reproducing apparatus

A perpendicular magnetic recording medium includes a perpendicular magnetic layer provided above a nonmagnetic substrate, and a protection layer provided on the perpendicular magnetic layer. The perpendicular magnetic layer has an hcp structure, and includes stacked layers having a (0002) crystal plane oriented parallel to a surface of the nonmagnetic substrate. An uppermost layer amongst the stacked layers includes polycrystal grains selected from a CoCr-base alloy, a CoPt-base alloy, a CoCrPt-base alloy, and a CoPtCr-base alloy. The protection layer makes contact with the uppermost layer of the perpendicular magnetic layer, and includes a single graphene layer or a graphene stack, and an amorphous carbon layer. The single graphene layer or the graphene stack is bonded in parallel to a (0002) crystal plane of the polycrystal grains.

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Chiba, Japan

Kota Hasegawa