公开(公告)号：US11024334B2

公开(公告)日：2021-06-01

申请号：US16835770

申请日：2020-03-31

Applicant: SHOWA DENKO K.K.

Inventor： Takayuki Fukushima ,  Chen Xu ,  Lei Zhang ,  Hisato Shibata ,  Takehiro Yamaguchi ,  Kazuya Niwa ,  Tomoo Shige ,  Hiroaki Nemoto ,  Yuji Umemoto ,  Hiroshi Koyanagi

IPC: G11B11/105 ,  G11B5/65 ,  G11B5/66 ,  G11B5/60 ,  G11B5/00

Abstract: A magnetic recording medium includes a substrate, an underlayer, and a magnetic layer that are arranged in this order. The magnetic layer has a granular structure including magnetic grains having a L10 crystal structure, and grain boundary parts having a volume fraction in a range of 25 volume % to 50 volume %. The magnetic grains have a c-axis orientation with respect to the substrate. The grain boundary parts include a material having a lattice constant in a range of 0.30 nm to 0.36 nm, or in a range of 0.60 nm to 0.72 nm.

公开(公告)号：US10127932B2

公开(公告)日：2018-11-13

申请号：US15088341

申请日：2016-04-01

Applicant: SHOWA DENKO K.K.

Inventor： Chen Xu ,  Gohei Kurokawa

IPC: G11B5/66 ,  G11B5/127 ,  G11B5/73

Abstract: A perpendicular magnetic recording medium includes a soft magnetic underlayer, an underlayer, an intermediate layer, and a perpendicular magnetic recording layer successively stacked on a nonmagnetic substrate. The soft magnetic underlayer includes a soft magnetic layer having an amorphous structure. The underlayer includes a first underlayer, and a second underlayer provided between the first underlayer and the intermediate layer. The first underlayer is made of a TiV alloy having an amorphous structure, and the second underlayer is made of an NiW alloy including at least one element selected from a group consisting of Co, Cu, Al, Cr, and Fe. The intermediate layer is made of Ru or an Ru alloy, and wherein the soft magnetic layer, the first underlayer, and the second underlayer are stacked in this order.

公开(公告)号：US11244700B2

公开(公告)日：2022-02-08

申请号：US16169065

申请日：2018-10-24

Applicant: SHOWA DENKO K.K.

Inventor： Katsumi Murofushi ,  Yoshitaka Ishibashi ,  Takayuki Fukushima ,  Kazuya Niwa ,  Lei Zhang ,  Yuji Murakami ,  Hisato Shibata ,  Takehiro Yamaguchi ,  Chen Xu ,  Tetsuya Kanbe ,  Tomoo Shige

IPC: G11B5/65 ,  G11B5/72 ,  G11B5/82 ,  G11B5/851 ,  C08L61/28

Abstract: A magnetic recording medium includes a substrate, an underlayer provided on the substrate, and a magnetic layer provided on the underlayer and having a L10 structure and a (001) orientation. The magnetic layer has a granular structure in which an organic compound having a methylene skeleton or a methine skeleton is arranged at grain boundaries of magnetic grains.

公开(公告)号：US10192571B2

公开(公告)日：2019-01-29

申请号：US15096351

申请日：2016-04-12

Applicant: SHOWA DENKO K.K.

Inventor： Chen Xu ,  Gohei Kurokawa

IPC: G11B5/73 ,  G11B5/667 ,  G11B5/127

Abstract: A perpendicular magnetic recording medium includes a structure in which at least a soft magnetic backing layer, an underlayer, an intermediate layer, and a perpendicular magnetic recording layer are sequentially laminated on a non-magnetic substrate, in which the soft magnetic backing layer includes at least a soft magnetic film having an amorphous structure, the underlayer includes a first underlayer and a second underlayer laminated in this order from the non-magnetic substrate side, the first underlayer is made of a TiV alloy having an amorphous structure, the second underlayer includes a NiW alloy, the intermediate layer includes Ru or a Ru alloy, the soft magnetic film having an amorphous structure directly contacts the first underlayer, and the first underlayer directly contacts the second underlayer.

公开(公告)号：US11676632B2

公开(公告)日：2023-06-13

申请号：US17104504

申请日：2020-11-25

Applicant: SHOWA DENKO K.K.

Inventor： Takayuki Fukushima ,  Lei Zhang ,  Chen Xu ,  Hisato Shibata ,  Takehiro Yamaguchi ,  Hiroshi Koyanagi ,  Yuji Umemoto

IPC: G11B5/73 ,  G11B5/851 ,  C23C14/08 ,  C23C14/34 ,  C23C14/00 ,  G11B5/716 ,  C23C14/35

CPC classification number: G11B5/736 ,  C23C14/0057 ,  C23C14/081 ,  C23C14/34 ,  C23C14/35 ,  G11B5/716 ,  G11B5/7369 ,  G11B5/851 ,  Y10T428/115

Abstract: The present invention relates to a magnetic recording medium including a substrate; an underlayer laminated upon the substrate; and a magnetic layer laminated upon the underlayer, wherein the underlayer includes a first underlayer containing a compound represented by a following general formula: MgO(1-X), where X is within a range of 0.07 to 0.25, the magnetic layer includes a first magnetic layer containing an alloy having a L10 structure, and the alloy having the L10 structure includes B, and the first underlayer is in contact with the first magnetic layer.

公开(公告)号：US11189313B2

公开(公告)日：2021-11-30

申请号：US17141367

申请日：2021-01-05

Applicant: SHOWA DENKO K.K.

Inventor： Koichi Nagasaka ,  Takayuki Fukushima ,  Lei Zhang ,  Chen Xu ,  Hisato Shibata ,  Takehiro Yamaguchi ,  Hiroshi Koyanagi ,  Yuji Umemoto

IPC: G11B5/70 ,  G11B5/706 ,  G11B5/73 ,  G11B5/33 ,  G11B5/851 ,  G11B5/716 ,  G11B5/66

Abstract: A magnetic recording medium includes a substrate, an underlayer provided above the substrate, and a magnetic layer provided on and in contact with the underlayer. The underlayer includes a compound represented by a general formula MgO(1-x), where x falls within a range of 0.07 to 0.25. The magnetic layer includes an alloy having a L10 structure, and the alloy having the L10 structure includes one or more elements selected from a group consisting of Al, Si, Ga, and Ge.

公开(公告)号：US11037591B2

公开(公告)日：2021-06-15

申请号：US16433377

申请日：2019-06-06

Applicant: SHOWA DENKO K.K.

Inventor： Lei Zhang ,  Chen Xu ,  Takayuki Fukushima ,  Kazuya Niwa ,  Tetsuya Kanbe ,  Hisato Shibata ,  Takehiro Yamaguchi ,  Tomoo Shige

IPC: G11B5/73 ,  G11B5/65 ,  G11B5/00

Abstract: A heat-assisted magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having an L10 structure, wherein the underlayer includes, from the substrate side, a bcc underlayer including a substance having a bcc structure, a first oxide layer that is in contact with the bcc underlayer, and a second oxide layer that is in contact with the magnetic layer. The bcc underlayer, the first oxide layer, and the second oxide layer are stacked in the recited order. The first oxide layer and the second oxide layer include magnesium oxide, and the second oxide layer further includes one or more compounds selected from the group consisting of vanadium oxide, vanadium nitride, and vanadium carbide.

公开(公告)号：US12087341B2

公开(公告)日：2024-09-10

申请号：US16862809

申请日：2020-04-30

Applicant: SHOWA DENKO K.K.

Inventor： Chen Xu ,  Lei Zhang ,  Takayuki Fukushima ,  Hisato Shibata ,  Takehiro Yamaguchi ,  Kazuya Niwa ,  Tomoo Shige ,  Hiroaki Nemoto ,  Yuji Umemoto ,  Hiroshi Koyanagi

IPC: G11B5/66 ,  G11B5/65 ,  G11B5/73

CPC classification number: G11B5/73919 ,  G11B5/657 ,  G11B5/658

Abstract: A magnetic recording medium includes a substrate, an underlayer formed on the substrate, and a magnetic layer formed on the underlayer. The magnetic layer includes an alloy having a L10 structure. The underlayer includes a first underlayer and a second underlayer. The first underlayer includes Mo and Ru, the content of Ru in the first underlayer is in a range of 5 atom % to 30 atom %, and the second underlayer includes a material having a body-centered cubic (BCC) structure. The second underlayer is formed between the first underlayer and the substrate.

公开(公告)号：US10978103B2

公开(公告)日：2021-04-13

申请号：US16407412

申请日：2019-05-09

Applicant: SHOWA DENKO K.K.

Inventor： Takayuki Fukushima ,  Kazuya Niwa ,  Lei Zhang ,  Hisato Shibata ,  Takehiro Yamaguchi ,  Chen Xu ,  Tetsuya Kanbe ,  Tomoo Shige

IPC: G11B5/66 ,  G11B5/64 ,  G11B5/65

Abstract: A magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having a L10 structure and a (001) orientation, wherein the substrate, the underlayer, and the magnetic layer are stacked in the recited order, and wherein the magnetic layer has a granular structure and includes a carbon hydride, a boron hydride, or a boron nitride hydride.

公开(公告)号：US10553242B2

公开(公告)日：2020-02-04

申请号：US16445801

申请日：2019-06-19

Applicant: SHOWA DENKO K.K.

Inventor： Lei Zhang ,  Takayuki Fukushima ,  Chen Xu ,  Kazuya Niwa ,  Hisato Shibata ,  Takehiro Yamaguchi ,  Tetsuya Kanbe ,  Tomoo Shige

IPC: G11B5/65 ,  G11B5/00

Abstract: A heat-assisted magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer that is (001)-oriented. In the magnetic layer, a first magnetic layer and a second magnetic layer are stacked in this order from the underlayer side. The first magnetic layer and the second magnetic layer include an alloy having an L10 structure. The second magnetic layer includes a ferrite at grain boundaries of magnetic grains. The ferrite is one or more kinds selected from the group consisting of NiFe2O4, MgFe2O4, MnFe2O4, CuFe2O4, ZnFe2O3, CoFe2O4, BaFe2O4, SrFe2O4, and Fe3O4. A Curie temperature of the magnetic grains is lower than a Curie temperature of the ferrite.