Carbon Substrate Patents (Class 428/846.5)
  • Patent number: 11640833
    Abstract: A disk-shaped substrate for a magnetic disk has a diameter D of 85 mm or more and a thickness T of 0.6 mm or less, and a material of the substrate has a Young's modulus E of 90 GPa or more.
    Type: Grant
    Filed: August 7, 2019
    Date of Patent: May 2, 2023
    Assignee: HOYA CORPORATION
    Inventor: Shinji Eda
  • Publication number: 20120028076
    Abstract: According to one embodiment, a magnetic recording medium includes a substrate, a soft magnetic layer, an underlayer, a magnetic recording layer, and a protective layer, wherein the magnetic recording layer is provided with a pattern including recording portions and non-recording portions, the non-recording portions have a composition that is equal to a composition obtained by demagnetizing the recording portions, the non-recording portions contain at least one metal element selected from the group consisting of vanadium and zirconium and at least one element selected from the group consisting of nitrogen, carbon, boron and oxygen, and the at least one element selected from the group consisting of nitrogen, carbon, boron and oxygen is contained in the non-recording portions at a higher content than the content of the at least one element selected from the group consisting of nitrogen, carbon, boron and oxygen in the recording portions.
    Type: Application
    Filed: July 1, 2011
    Publication date: February 2, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takeshi Iwasaki, Kaori Kimura, Yoshiyuki Kamata, Masatoshi Sakurai
  • Publication number: 20080292909
    Abstract: This magnetic recording medium has a substrate, a nonmagnetic granular layer formed above the substrate and a recording layer formed on the nonmagnetic granular layer. The nonmagnetic granular layer is made of CoCr alloy with an hcp or an fcc crystal structure in which a nonmagnetic material segregates virtually-columnar magnetic grains. The magnetic recording medium and the magnetic storage apparatus in which the medium is used have improved reading/writing performances.
    Type: Application
    Filed: May 2, 2008
    Publication date: November 27, 2008
    Applicant: FUJITSU LIMITED
    Inventors: Satoshi Igarashi, Akira Kikuchi, Isatake Kaitsu, Ryosaku Inamura, Kenji Sato, Shinya Sato, Hideaki Takahoshi, Atsushi Endo, Hisato Shibata