公开(公告)号：US09640213B2

公开(公告)日：2017-05-02

申请号：US14935529

申请日：2015-11-09

Applicant: SHOWA DENKO K.K. ,  JAPAN ATOMIC ENERGY AGENCY

Inventor： Kota Hasegawa ,  Takahiro Ukai ,  Eishin Yamakawa ,  Shiro Entani ,  Seiji Sakai

IPC: G11B5/66 ,  G11B5/72 ,  G11B5/82

CPC classification number: G11B5/72 ,  G11B5/66 ,  G11B5/82

Abstract: 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.

公开(公告)号：US11823721B2

公开(公告)日：2023-11-21

申请号：US17649588

申请日：2022-02-01

Applicant: SHOWA DENKO K.K.

Inventor： Yoshitaka Aono ,  Takahiro Ukai ,  Takanao Ebisawa ,  Kazuya Niwa ,  Takayuki Konno

IPC: G11B5/667 ,  G11B5/66 ,  G11B5/851

CPC classification number: G11B5/667 ,  G11B5/672 ,  G11B5/851

Abstract: A magnetic recording medium including: a non-magnetic substrate; an underlayer; a perpendicular magnetic layer; a diffusion preventing layer; and a protective layer, wherein the underlayer, the perpendicular magnetic layer, the diffusion preventing layer, and the protective layer are layered on the non-magnetic substrate in this order, the perpendicular magnetic layer has a multi-layer structure, the perpendicular magnetic layer includes an uppermost layer and at least one layer other than the uppermost layer, the uppermost layer including Co or Fe in magnetic particles, and the at least one layer other than the uppermost layer including an oxide, the diffusion preventing layer is provided between the perpendicular magnetic layer and the protective layer, and the diffusion preventing layer includes at least one component selected from a group consisting of Si, Ti, Cr, B, and Ru, or either a carbide, an oxide, or both, of the at least one component.

公开(公告)号：US12217779B2

公开(公告)日：2025-02-04

申请号：US18146647

申请日：2022-12-27

Applicant: SHOWA DENKO K.K.

Inventor： Yoshitaka Aono ,  Takahiro Ukai ,  Takanao Ebisawa ,  Kazuya Niwa ,  Takayuki Konno

IPC: G11B5/667 ,  G11B5/66 ,  G11B5/851

Abstract: A method of manufacturing a magnetic recording medium including: forming a diffusion preventing layer, wherein the magnetic recording medium includes a non-magnetic substrate; an underlayer; a perpendicular magnetic layer; the diffusion preventing layer; and a protective layer, wherein the perpendicular magnetic layer has a multi-layer structure, the perpendicular magnetic layer includes an uppermost layer and at least one layer other than the uppermost layer, the uppermost layer including Co or Fe in magnetic particles, and the at least one layer other than the uppermost layer including an oxide, the diffusion preventing layer is provided between the perpendicular magnetic layer and the protective layer, and the diffusion preventing layer includes at least one component selected from a group consisting of Si, Ti, Cr, B, and Ru, or either a carbide, an oxide, or both, of the at least one component.