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：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：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：US11043238B1

公开(公告)日：2021-06-22

申请号：US17116223

申请日：2020-12-09

Applicant: SHOWA DENKO K.K.

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

IPC: G11B5/73 ,  G11B5/706

Abstract: A magnetic recording medium includes a substrate; a soft magnetic underlayer laminated on the substrate; an amorphous barrier layer laminated on the soft magnetic underlayer; and a magnetic recording layer laminated on the amorphous barrier layer, wherein the soft magnetic underlayer includes Fe, B, Si, and one or more elements selected from the group consisting of Nb, Zr, Mo, and Ta, wherein the amorphous barrier layer includes Si, W, and one or more elements selected from the group consisting of Nb, Zr, Mo, and Ta, and wherein the magnetic recording layer includes an alloy having an L10 structure.

公开(公告)号：US10685674B2

公开(公告)日：2020-06-16

申请号：US16445772

申请日：2019-06-19

Applicant: SHOWA DENKO K.K.

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

IPC: G11B5/56 ,  G11B5/65 ,  G11B5/00

Abstract: A magnetic recording medium includes: a substrate; an underlayer; a magnetic layer including an alloy having an L10 type crystal structure; and a protective layer, wherein the substrate, the underlayer, the magnetic layer, and the protective layer are stacked in the recited order. A pinning layer is further included between the magnetic layer and the protective layer, and the pinning layer includes a magnetic material including Co and includes at least one metal selected from the group consisting of Cu, Ag, Au, and Al.