Patents by Inventor Tomoo Shige

Tomoo Shige has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11545176
    Abstract: A magnetic recording medium includes a substrate, and a magnetic recording layer including magnetic grains having an L10 structure. The magnetic recording layer is (001) oriented, and a surface of growth of the magnetic recording layer includes a (001) plane, a (111) plane, and planes equivalent to the (111) plane. An area ratio of the (111) plane and the planes equivalent to the (111) plane, represented by (A111+A111e)/(A001+A111+A111e), is in a range of 0.2 to 0.7, where A111 denotes an area of the (111) plane, A111e denotes an area of the planes equivalent to the (111) plane, and A001 denotes an area of the (001) plane.
    Type: Grant
    Filed: April 5, 2022
    Date of Patent: January 3, 2023
    Assignee: SHOWA DENKO K.K.
    Inventors: Takayuki Fukushima, Tomoo Shige, Yuji Umemoto, Kazuya Niwa
  • Publication number: 20220358962
    Abstract: A magnetic recording medium includes a substrate, and a magnetic recording layer including magnetic grains having an L10 structure. The magnetic recording layer is (001) oriented, and a surface of growth of the magnetic recording layer includes a (001) plane, a (111) plane, and planes equivalent to the (111) plane. An area ratio of the (111) plane and the planes equivalent to the (111) plane, represented by (A111+A111e)/(A001+A111+A111e), is in a range of 0.2 to 0.7, where A111 denotes an area of the (111) plane, A111e denotes an area of the planes equivalent to the (111) plane, and A001 denotes an area of the (001) plane.
    Type: Application
    Filed: April 5, 2022
    Publication date: November 10, 2022
    Inventors: Takayuki FUKUSHIMA, Tomoo SHIGE, Yuji UMEMOTO, Kazuya NIWA
  • Publication number: 20220319546
    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.
    Type: Application
    Filed: March 29, 2022
    Publication date: October 6, 2022
    Inventors: Chen XU, Gohei KUROKAWA, Lei ZHANG, Takayuki FUKUSHIMA, Tomoo SHIGE, Shin SAITO
  • Patent number: 11244700
    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.
    Type: Grant
    Filed: October 24, 2018
    Date of Patent: February 8, 2022
    Assignee: SHOWA DENKO K.K.
    Inventors: Katsumi Murofushi, Yoshitaka Ishibashi, Takayuki Fukushima, Kazuya Niwa, Lei Zhang, Yuji Murakami, Hisato Shibata, Takehiro Yamaguchi, Chen Xu, Tetsuya Kanbe, Tomoo Shige
  • Patent number: 11037591
    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.
    Type: Grant
    Filed: June 6, 2019
    Date of Patent: June 15, 2021
    Assignee: SHOWA DENKO K.K.
    Inventors: Lei Zhang, Chen Xu, Takayuki Fukushima, Kazuya Niwa, Tetsuya Kanbe, Hisato Shibata, Takehiro Yamaguchi, Tomoo Shige
  • Patent number: 11024334
    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.
    Type: Grant
    Filed: March 31, 2020
    Date of Patent: June 1, 2021
    Assignee: SHOWA DENKO K.K.
    Inventors: Takayuki Fukushima, Chen Xu, Lei Zhang, Hisato Shibata, Takehiro Yamaguchi, Kazuya Niwa, Tomoo Shige, Hiroaki Nemoto, Yuji Umemoto, Hiroshi Koyanagi
  • Patent number: 10978103
    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.
    Type: Grant
    Filed: May 9, 2019
    Date of Patent: April 13, 2021
    Assignee: SHOWA DENKO K.K.
    Inventors: Takayuki Fukushima, Kazuya Niwa, Lei Zhang, Hisato Shibata, Takehiro Yamaguchi, Chen Xu, Tetsuya Kanbe, Tomoo Shige
  • Publication number: 20200357436
    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.
    Type: Application
    Filed: April 30, 2020
    Publication date: November 12, 2020
    Inventors: Chen XU, Lei ZHANG, Takayuki FUKUSHIMA, Hisato SHIBATA, Takehiro YAMAGUCHI, Kazuya NIWA, Tomoo SHIGE, Hiroaki NEMOTO, Yuji UMEMOTO, Hiroshi KOYANAGI
  • Publication number: 20200327905
    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.
    Type: Application
    Filed: March 31, 2020
    Publication date: October 15, 2020
    Inventors: Takayuki FUKUSHIMA, Chen XU, Lei ZHANG, Hisato SHIBATA, Takehiro YAMAGUCHI, Kazuya NIWA, Tomoo SHIGE, Hiroaki NEMOTO, Yuji UMEMOTO, Hiroshi KOYANAGI
  • Patent number: 10685674
    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.
    Type: Grant
    Filed: June 19, 2019
    Date of Patent: June 16, 2020
    Assignee: SHOWA DENKO K.K.
    Inventors: Takayuki Fukushima, Hisato Shibata, Yuji Umemoto, Kazuya Niwa, Lei Zhang, Takehiro Yamaguchi, Chen Xu, Tomoo Shige, Hiroshi Koyanagi
  • Patent number: 10643649
    Abstract: A heat-assisted magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having an L10 structure. The substrate, the underlayer, and the magnetic layer are stacked in the recited order. The underlayer includes a first underlayer. The first underlayer includes magnesium oxide and one or more compounds selected from the group consisting of vanadium oxide, zinc oxide, tin oxide, vanadium nitride, and vanadium carbide, and a total content of the one or more compounds is in a range of 45 mol % to 70 mol %.
    Type: Grant
    Filed: June 21, 2019
    Date of Patent: May 5, 2020
    Assignees: SHOWA DENKO K.K., TOHOKU UNIVERSITY
    Inventors: Shin Saito, Takayuki Fukushima, Lei Zhang, Hisato Shibata, Takehiro Yamaguchi, Chen Xu, Tetsuya Kanbe, Tomoo Shige, Kazuya Niwa, Atsushi Hashimoto
  • Patent number: 10614849
    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.
    Type: Grant
    Filed: July 23, 2019
    Date of Patent: April 7, 2020
    Assignee: SHOWA DENKO K.K.
    Inventors: Takayuki Fukushima, Koji Take, Hisato Shibata, Takehiro Yamaguchi, Tomoo Shige, Lei Zhang, Chen Xu, Yuji Umemoto, Hiroshi Koyanagi, Kazuya Niwa, Tetsuya Kanbe
  • Publication number: 20200075053
    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.
    Type: Application
    Filed: July 23, 2019
    Publication date: March 5, 2020
    Inventors: Takayuki FUKUSHIMA, Koji TAKE, Hisato SHIBATA, Takehiro YAMAGUCHI, Tomoo SHIGE, Lei ZHANG, Chen XU, Yuji UMEMOTO, Hiroshi KOYANAGI, Kazuya NIWA, Tetsuya KANBE
  • Patent number: 10553242
    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.
    Type: Grant
    Filed: June 19, 2019
    Date of Patent: February 4, 2020
    Assignee: SHOWA DENKO K.K.
    Inventors: Lei Zhang, Takayuki Fukushima, Chen Xu, Kazuya Niwa, Hisato Shibata, Takehiro Yamaguchi, Tetsuya Kanbe, Tomoo Shige
  • Publication number: 20200005821
    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.
    Type: Application
    Filed: June 19, 2019
    Publication date: January 2, 2020
    Inventors: Lei ZHANG, Takayuki FUKUSHIMA, Chen XU, Kazuya NIWA, Hisato SHIBATA, Takehiro YAMAGUCHI, Tetsuya KANBE, Tomoo SHIGE
  • Publication number: 20200005823
    Abstract: A heat-assisted magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having an L10 structure. The substrate, the underlayer, and the magnetic layer are stacked in the recited order. The underlayer includes a first underlayer. The first underlayer includes magnesium oxide and one or more compounds selected from the group consisting of vanadium oxide, zinc oxide, tin oxide, vanadium nitride, and vanadium carbide, and a total content of the one or more compounds is in a range of 45 mol % to 70 mol %.
    Type: Application
    Filed: June 21, 2019
    Publication date: January 2, 2020
    Inventors: Shin SAITO, Takayuki FUKUSHIMA, Lei ZHANG, Hisato SHIBATA, Takehiro YAMAGUCHI, Chen XU, Tetsuya KANBE, Tomoo SHIGE, Kazuya NIWA, Atsushi HASHIMOTO
  • Publication number: 20190392863
    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.
    Type: Application
    Filed: June 19, 2019
    Publication date: December 26, 2019
    Inventors: Takayuki FUKUSHIMA, Hisato SHIBATA, Yuji UMEMOTO, Kazuya NIWA, Lei ZHANG, Takehiro YAMAGUCHI, Chen XU, Tomoo SHIGE, Hiroshi KOYANAGI
  • Publication number: 20190392860
    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.
    Type: Application
    Filed: June 6, 2019
    Publication date: December 26, 2019
    Inventors: Lei ZHANG, Chen XU, Takayuki FUKUSHIMA, Kazuya NIWA, Tetsuya KANBE, Hisato SHIBATA, Takehiro YAMAGUCHI, Tomoo SHIGE
  • Publication number: 20190355387
    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.
    Type: Application
    Filed: May 9, 2019
    Publication date: November 21, 2019
    Inventors: Takayuki FUKUSHIMA, Kazuya NIWA, Lei ZHANG, Hisato SHIBATA, Takehiro YAMAGUCHI, Chen XU, Tetsuya KANBE, Tomoo SHIGE
  • Publication number: 20190325906
    Abstract: A magnetic recording device includes a substrate, an intermediate layer disposed on the substrate, a magnetic recording layer disposed on the intermediate layer, and a graphene overcoat disposed on the magnetic recording layer. The graphene overcoat includes at least one layer of a graphene monoatomic layer which is a sheet-like monoatomic layer of sp2 bonded carbon atoms. A transition layer is interposed between the graphene overcoat and the magnetic recording layer. The transition layer includes carbon and at least one metal of the magnetic recording layer.
    Type: Application
    Filed: July 2, 2019
    Publication date: October 24, 2019
    Inventors: Moon-Sun Lin, TOMOO SHIGE, Shih-Chin Chen, Yu-Lun Chueh, Li-Chia Yang, Yu-Ze Chen, Yao-Jen Kuo