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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
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.
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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
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.
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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.
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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.
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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
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 %.
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Patent Agency Ranking
公开(公告)号：US20220310119A1
公开(公告)日：2022-09-29
申请号：US17650119
申请日：2022-02-07
Applicant: SHOWA DENKO K.K.
Inventor： Takehiro YAMAGUCHI , Hisato SHIBATA , Takayuki FUKUSHIMA , Chen XU
Abstract: A magnetic recording medium includes a substrate, an underlayer provided on the substrate and including MgO, and a magnetic layer provided on the underlayer and including an alloy having a L10 crystal structure. The magnetic layer includes first, second, and third magnetic recording layers successively provided in this order above the underlayer. A Curie temperature of the second magnetic recording layer is lower than a Curie temperature of each of the first and third magnetic recording layers, by a value which falls within a range of 30 K to 100 K. An average grain diameter of magnetic grains at a bottom surface portion of the first magnetic recording layer is smaller by 15% or more than average grain diameters of magnetic grains at bottom surface portions of the second and third magnetic recording layers.
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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.
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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.
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9.发明申请公开(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
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.
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公开(公告)号：US20200327905A1
公开(公告)日：2020-10-15
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
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.
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