Patents by Inventor Tatsu Komatsuda

Tatsu Komatsuda 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: 8512884
    Abstract: A perpendicular magnetic recording medium including at least a soft under layer, an orientation control layer, a magnetic recording layer and a protective layer on a non-magnetic substrate, wherein the orientation control layer is composed of three or more layers including a seed layer, a first intermediate layer and a second intermediate layer sequentially, formed in that order from the substrate side, the crystal grains that constitute the first intermediate layer are epitaxially grown on the crystal grains of the seed layer, the crystal grains that constitute the second intermediate layer are epitaxially grown on the crystal grains of the first intermediate layer, and the crystal grains that constitute the second intermediate layer are finer than the crystal grains that constitute the first intermediate layer.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: August 20, 2013
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba, Tohoku University
    Inventors: Migaku Takahashi, Shin Saito, Gohei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Atsushi Hashimoto, Akihiko Takeo, Tomoyuki Maeda
  • Patent number: 8133601
    Abstract: A magnetic recording medium is provided which can record and reproduce high-density information by maintaining perpendicular orientation of a magnetic recording layer even with a decrease in thickness of nonmagnetic layers from an intermediate layer to a seed layer while decreasing the grain size of magnetic crystal grains to be consistent with an increase in recording density. A manufacturing method thereof and a magnetic recording and reproducing apparatus are also provided. The magnetic recording medium is a perpendicular magnetic recording medium including at least an underlying layer, an orientation control layer, a magnetic recording layer, and a protective layer formed on a nonmagnetic substrate. Here, the orientation control layer includes two or more layers of a seed layer and an intermediate layer from the substrate side.
    Type: Grant
    Filed: August 25, 2008
    Date of Patent: March 13, 2012
    Assignee: Showa Denko K.K.
    Inventors: Gohei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Atsushi Hashimoto
  • Publication number: 20110151280
    Abstract: A perpendicular magnetic recording medium including at least a soft under layer, an orientation control layer, a magnetic recording layer and a protective layer on a non-magnetic substrate, wherein the orientation control layer is composed of three or more layers including a seed layer, a first intermediate layer and a second intermediate layer sequentially, formed in that order from the substrate side, the crystal grains that constitute the first intermediate layer are epitaxially grown on the crystal grains of the seed layer, the crystal grains that constitute the second intermediate layer are epitaxially grown on the crystal grains of the first intermediate layer, and the crystal grains that constitute the second intermediate layer are finer than the crystal grains that constitute the first intermediate layer.
    Type: Application
    Filed: August 28, 2008
    Publication date: June 23, 2011
    Applicant: SHOWA DENKO K.K.
    Inventors: Migaku Takahashi, Shin Saito, Gohei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Atsushi Hashimoto, Akihiko Takeo, Tomoyuki Maeda
  • Publication number: 20110111257
    Abstract: A magnetic recording medium is provided which can record and reproduce high-density information by maintaining perpendicular orientation of a magnetic recording layer even with a decrease in thickness of nonmagnetic layers from an intermediate layer to a seed layer while decreasing the grain size of magnetic crystal grains to be consistent with an increase in recording density. A manufacturing method thereof and a magnetic recording and reproducing apparatus are also provided. The magnetic recording medium is a perpendicular magnetic recording medium including at least an underlying layer, an orientation control layer, a magnetic recording layer, and a protective layer formed on a nonmagnetic substrate. Here, the orientation control layer includes two or more layers of a seed layer and an intermediate layer from the substrate side.
    Type: Application
    Filed: August 25, 2008
    Publication date: May 12, 2011
    Applicant: SHOWA DENKO K.K.
    Inventors: Gohei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Atsushi Hashimoto
  • Publication number: 20100247961
    Abstract: In a perpendicular magnetic recording medium having at least a soft magnetic back layer, an underlayer, an intermediate layer and a perpendicular magnetic recording layer on a nonmagnetic substrate, at least one layer in the intermediate layer contains Re as a main component element and contains, as a second main component element, an element having an hcp structure or an element having a bcc structure. The concentration of Re as the main component element of the intermediate layer is within the range from 55 to 99.5 atomic percent. The second component element is Co or Cr.
    Type: Application
    Filed: January 16, 2008
    Publication date: September 30, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Ryuji Sakaguchi, Gohei Kurokawak, Yuzo Sasaki, Tatsu Komatsuda, Amarendra K. Singh
  • Publication number: 20100215991
    Abstract: A perpendicular magnetic recording medium is provided, which has a soft magnetic layer, a seed layer, a first intermediate layer, a second intermediate layer and a perpendicular magnetic recording layer, formed in this order on a non-magnetic substrate, and is characterized in that the seed layer is comprised of a (002) crystal plane-orientated hcp structure, the first intermediate layer is comprised of a (110) crystal plane-orientated bcc structure and the second intermediate layer is comprised of a (002) crystal plane-orientated hcp structure. The (110) crystal plane-orientated bcc structure comprises at least 60 atomic % of Cr. The magnetic recording medium has fine and well discrete magnetic crystal grains with extremely small size and exhibits good perpendicular orientation in the perpendicular magnetic recording layer, and thus, the medium is capable of recording and reproducing information with high density.
    Type: Application
    Filed: July 25, 2008
    Publication date: August 26, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Gohei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Atsushi Hashimoto
  • Publication number: 20100136370
    Abstract: The present invention provides a magnetic recording medium capable of reducing the diameter of particles of a perpendicular magnetic recording layer and obtaining a high perpendicular orientation to enable information to be recorded or reproduced at a high density, a method of manufacturing the same, and a magnetic recording/reproducing apparatus. A perpendicular magnetic recording medium includes a non-magnetic substrate; and at least a soft magnetic layer, an underlayer, an intermediate layer, and a perpendicular magnetic recording layer that are formed on the non-magnetic substrate in this order. The underlayer is a (111) crystal orientation layer having an fcc structure, and the intermediate layer includes a (110) crystal orientation layer having a bcc structure and a (002) crystal orientation layer having an hcp structure in this order. The (110) crystal orientation layer having the bcc structure includes 60 at % or more of Cr.
    Type: Application
    Filed: February 19, 2008
    Publication date: June 3, 2010
    Inventors: Ryuji Sakaguchi, Gohei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Amarendra K. Singh
  • Publication number: 20100079911
    Abstract: A perpendicular magnetic recording medium is provided, which has a backing layer, a primer layer, an intermediate layer and at least one perpendicular magnetic recording layer, and is characterized in that the perpendicular magnetic recording layer contains Co and Cr, and at least one of the perpendicular magnetic recording layer or layers has a granular structure comprising ferromagnetic crystal grains and grain boundaries comprised of non-magnetic tungsten oxide. The perpendicular magnetic recording layer may be a double-layered structure comprising the tungsten oxide grain boundary-containing layer and a Cr oxide, Si oxide, Ta oxide or Ti oxide grain boundary-containing layer formed on the tungsten oxide grain boundary-containing layer. The perpendicular magnetic recording medium exhibits good perpendicular orientation and has ferromagnetic crystal grains with extremely small grain size, and thus, is superior in high recording density characteristic.
    Type: Application
    Filed: April 28, 2008
    Publication date: April 1, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Ryuji Sakaguchi, Gouhei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Amarendra Singh