公开(公告)号：US20210201944A1

公开(公告)日：2021-07-01

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: G11B5/706

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：US20190392863A1

公开(公告)日：2019-12-26

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: G11B5/65

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.

公开(公告)号：US20180226092A1

公开(公告)日：2018-08-09

申请号：US15859989

申请日：2018-01-02

Applicant: SHOWA DENKO K.K.

Inventor： Takayuki FUKUSHIMA ,  Haruhisa OHASHI ,  Lei ZHANG ,  Yuji MURAKAMI ,  Hisato SHIBATA ,  Takehiro YAMAGUCHI ,  Tetsuya KANBE

IPC: G11B5/65 ,  G11B5/66

Abstract: A magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having a L10 type crystal structure whose plane orientation is (001). The substrate, the underlayer, and the magnetic layer are stacked in this order. The underlayer includes a first underlayer. The first underlayer is a crystalline layer that includes a material containing Al, Ag, Cu, W, or Mo as a main component element and includes an oxide of the main component element, a content of the oxide of the main component element in the first underlayer being in a range of from 2 mol % to 30 mol %.

公开(公告)号：US20200075053A1

公开(公告)日：2020-03-05

申请号：US16519157

申请日：2019-07-23

Applicant: SHOWA DENKO K.K.

Inventor： Takayuki FUKUSHIMA ,  Koji TAKE ,  Hisato SHIBATA ,  Takehiro YAMAGUCHI ,  Tomoo SHIGE ,  Lei ZHANG ,  Chen XU ,  Yuji UMEMOTO ,  Hiroshi KOYANAGI ,  Kazuya NIWA ,  Tetsuya KANBE

IPC: G11B11/105 ,  G11B5/73 ,  G11B11/24

Abstract: A heat-assisted magnetic recording medium includes a substrate, an underlayer, and a magnetic layer including an alloy having a L10 crystal structure and first and second layers, arranged in this order. Each of the first and second layers has a granular structure including C, SiO2, and BN at grain boundaries. Vol % of the grain boundaries in each of the first and second layers is 25 to 45 vol %. Vol % of C in the first layer is 5 to 22 vol %, and a volume ratio of SiO2 with respect to BN in each of the first and second layers is 0.25 to 3.5. Vol % of SiO2 in the second layer is greater than that of the first layer by 5 vol % or more. Vol % of BN in the second layer is smaller than that in the first layer by 2 vol % or more.

公开(公告)号：US20200005821A1

公开(公告)日：2020-01-02

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

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.

公开(公告)号：US20190180782A1

公开(公告)日：2019-06-13

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: G11B5/851 ,  G11B5/65 ,  G11B5/72 ,  G11B5/82

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：US20220381738A1

公开(公告)日：2022-12-01

申请号：US17804659

申请日：2022-05-31

Applicant: SHOWA DENKO K.K.

Inventor： Lei ZHANG ,  Fumito KUDO ,  Yuki HIRAI ,  Masayuki MAKITA ,  Kensuke YAMANAKA

IPC: G01N27/72 ,  G01N1/44

Abstract: A magnetic property measuring apparatus measures magnetic properties of a magnetic recording medium, and includes a rotating mechanism which rotates the magnetic recording medium, a heating or cooling mechanism which heats or cools the magnetic recording medium; a temperature measuring mechanism which measures a temperature of the magnetic recording medium, a laser heating mechanism, disposed opposite to a measurement site of the magnetic recording medium, which heats the measurement site without making contact with the measurement site, a magnetic write part, disposed opposite to the measurement site, which magnetizes the measurement site without making contact with the measurement site, and a magnetic read part, disposed opposite to the measurement site, which reads a magnetic flux leakage at the measurement site without making contact with the measurement site.

公开(公告)号：US20220319546A1

公开(公告)日：2022-10-06

申请号：US17656964

申请日：2022-03-29

Applicant: SHOWA DENKO K.K. ,  TOHOKU UNIVERSITY

Inventor： Chen XU ,  Gohei KUROKAWA ,  Lei ZHANG ,  Takayuki FUKUSHIMA ,  Tomoo SHIGE ,  Shin SAITO

IPC: G11B5/66 ,  G11B5/851

Abstract: A magnetic recording medium includes a magnesium oxide underlayer including magnesium oxide, and a magnetic layer including an alloy having a L10 structure and includes Fe or Co and Pt. The magnesium oxide has a peak of an O1s spectrum detected in a range of 531 eV to 533 eV when measured by X-ray photoelectron spectroscopy.

公开(公告)号：US20210256998A1

公开(公告)日：2021-08-19

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: G11B5/73 ,  G11B5/851 ,  G11B5/33

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：US20180240487A1

公开(公告)日：2018-08-23

申请号：US15868239

申请日：2018-01-11

Applicant: SHOWA DENKO K.K.

Inventor： Kazuya NIWA ,  Lei ZHANG ,  Yuji MURAKAMI ,  Hisato SHIBATA ,  Takayuki FUKUSHIMA ,  Takehiro YAMAGUCHI ,  Tetsuya KANBE

IPC: G11B5/65 ,  G11B5/48

CPC classification number: G11B5/65 ,  G11B5/4866 ,  G11B5/667 ,  G11B5/706 ,  G11B5/7325 ,  G11B2005/0021

Abstract: A magnetic recording medium includes a substrate, a first heat sink layer, a barrier layer, a second heat sink layer, and a magnetic layer that are successively stacked. The magnetic layer is made of a material including a first main component that is an alloy having a L10 crystal structure and a content of 50 at % or higher, or content of 50 mol % or higher. The barrier layer is made of a material including a second main component that is one of an oxide, a nitride, and a carbide having a content of 50 at % or higher, or content of 50 mol % or higher.