Patents by Inventor Yuzo Sasaki

Yuzo Sasaki 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: 8367229
    Abstract: The present invention relates to a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic layer (SUL), an alignment control layer, a magnetic recording layer and a protective layer formed on the nonmagnetic substrate, wherein the magnetic recording layer is constituted of two or more layers and includes a first magnetic recording layer and a second magnetic recording layer from the nonmagnetic substrate side and, regarding magnetocrystalline anisotropic energy Ku of each magnetic recording layer, the first magnetic recording layer has 4×106 erg/cc or higher and the second magnetic recording layer has 2×106 erg/cc or lower, wherein the first magnetic recording layer is constituted of CoCrPtRu magnetic alloy crystal grains and grain boundaries made of an oxide and the area of grain boundaries is 30% or more based on the entire area in a planar TEM observation of the first magnetic recording layer.
    Type: Grant
    Filed: September 30, 2008
    Date of Patent: February 5, 2013
    Assignee: Showa Denko K.K.
    Inventor: Yuzo Sasaki
  • Patent number: 8367155
    Abstract: There is provided a manufacturing method of a magnetic recording medium that maintains a high level of perpendicular orientation of a perpendicular magnetic layer and enables to further increase high recording density, prepared such that at least on a non-magnetic substrate, there are laminated a soft magnetic base layer, an orientation control layer 11 that controls the orientation of the layer immediately thereabove, and a perpendicular magnetic layer with a magnetization easy axis thereof primarily oriented perpendicular to the non-magnetic substrate.
    Type: Grant
    Filed: January 26, 2010
    Date of Patent: February 5, 2013
    Assignee: Showa Denko K.K.
    Inventors: Atsushi Hashimoto, Yuzo Sasaki, Gohei Kurokawa
  • Patent number: 8279739
    Abstract: A heat-assisted magnetic recording medium that includes a substrate, underlayers formed on the substrate, and a magnetic layer which is formed on the underlayers and contains either an FePt alloy having an L10 structure or a CoPt alloy having an L10 structure as a main component, wherein the underlayers include a first underlayer formed from an amorphous alloy, a second underlayer formed from an alloy having a BCC structure containing Cr as a main component and also containing at least one element selected from among Ti, Mo, W, V, Mn and Ru, and a third underlayer formed from MgO. Also, a magnetic storage device that uses the heat-assisted magnetic recording medium.
    Type: Grant
    Filed: August 19, 2010
    Date of Patent: October 2, 2012
    Assignee: Showa Denko K.K.
    Inventors: Tetsuya Kanbe, Yuzo Sasaki, Atsushi Hashimoto
  • Patent number: 8274653
    Abstract: The present invention provides a small spectroscope that has a short response time. A spectroscope according to one embodiment of the present invention includes: a beam deflector that includes an electro-optic crystal, having an electro-optic effect, and paired electrodes used to apply an electric field inside the electro-optic crystal; spectroscopic means for dispersing light output by the beam deflector; and wavelength selection means for selecting light having an arbitrary wavelength from the light dispersed and output by the spectroscopic means.
    Type: Grant
    Filed: July 30, 2008
    Date of Patent: September 25, 2012
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Koichiro Nakamura, Yuzo Sasaki, Kazuo Fujiura, Shogo Yagi
  • Patent number: 8247094
    Abstract: The present invention relates to a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic layer (SUL), an alignment control layer, a magnetic recording layer and a protective layer formed on the nonmagnetic substrate; wherein the magnetic recording layer is constituted of three or more layers and includes a first magnetic recording layer, a second magnetic recording layer and a third magnetic recording layer from the substrate side, and also includes an exchange coupling reduction layer for reducing exchange coupling of both layers between the second magnetic recording layer and the third magnetic recording layer and, regarding magnetocrystalline anisotropic energy Ku of each magnetic recording layer, the first magnetic recording layer has 4×106 erg/cc or higher, the second magnetic recording layer has 2×106 erg/cc or lower and the third magnetic recording layer has 1×106 erg/cc or lower.
    Type: Grant
    Filed: October 2, 2008
    Date of Patent: August 21, 2012
    Assignee: Showa Denko K.K.
    Inventor: Yuzo Sasaki
  • Publication number: 20120113768
    Abstract: A heat-assisted magnetic recording medium that includes a substrate 1, underlayers formed on the substrate 1, and a magnetic layer 5 which is formed on the underlayers and contains either an FePt alloy having an L10 structure or a CoPt alloy having an L10 structure as a main component, wherein the underlayers include a first underlayer 2 formed from an amorphous alloy, a second underlayer 3 formed from an alloy having a BCC structure containing Cr as a main component and also containing at least one element selected from among Ti, Mo, W, V, Mn and Ru, and a third underlayer 4 formed from MgO. Also, a magnetic storage device that uses the heat-assisted magnetic recording medium.
    Type: Application
    Filed: August 19, 2010
    Publication date: May 10, 2012
    Applicant: SHOWA DENKO K.K.
    Inventors: Tetsuya Kanbe, Yuzo Sasaki, Atsushi Hashimoto
  • 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
  • Patent number: 8034471
    Abstract: In a perpendicular magnetic recording medium in which at least a soft magnetic underlayer, an orientation control layer, a magnetic recording layer and a protective layer are formed on a non-magnetic substrate in order from the bottom, the orientation control layer has a laminated structure of two or more layers including an intermediate layer and a seed layer which is disposed closer to the non-magnetic substrate than the intermediate layer. The seed layer includes two or more kinds of elements having a face-centered cubic structure, has face-centered cubic (111) plane crystals oriented in a direction perpendicular to a substrate surface, and has a pseudo-hexagonal structure.
    Type: Grant
    Filed: August 5, 2009
    Date of Patent: October 11, 2011
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba, Tohoku University
    Inventors: Shinichi Ishibashi, Migaku Takahashi, Shin Saito, Yuzo Sasaki, Atsushi Hashimoto, Gohei Kurokawa, Tomoyuki Maeda, Akihiko Takeo
  • Patent number: 8034472
    Abstract: The present invention provides a magnetic recording medium which is capable of improving the perpendicular orientation of a perpendicular magnetic recording layer while maintaining a writing performance during recording and obtaining both an improvement in the perpendicular orientation and fine magnetic crystal particles with a uniform diameter, and which enables information to be recorded or reproduced at high density, a method of manufacturing the same, and a magnetic recording/reproducing apparatus. A magnetic recording medium 10 according to the present invention includes at least a soft magnetic underlayer 2, an orientation control layer 3, a magnetic recording layer 4, and a protective layer 5 formed on a non-magnetic substrate 1. The orientation control layer 3 has a seed layer 6 and an intermediate layer 7. The seed layer 6 is made of a Cu—Ti alloy that has a face-centered cubic structure and includes Cu as a main component.
    Type: Grant
    Filed: August 17, 2009
    Date of Patent: October 11, 2011
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba, Tohoku University
    Inventors: Shinichi Ishibashi, Migaku Takahashi, Shin Saito, Yuzo Sasaki, Atsushi Hashimoto, Gohei Kurokawa, Tomoyuki Maeda, Akihiko Takeo
  • Patent number: 8012613
    Abstract: A magnetic recording medium is provided, which has at least one soft magnetic layer, at least one seed layer, at least one underlayer and at least one perpendicular magnetic recording layer, and is characterized in that the or each seed layer is comprised of a covalently bonded material. The covalently bonded material preferably predominantly comprises a nitride having a hexagonal crystal structure, more preferably, predominantly comprises aluminum nitride having a hexagonal wurtzite crystal structure. This magnetic recording medium is superior in recording and reproducing an information with high density.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: September 6, 2011
    Assignees: Showa Denko K.K., Toshiba Corporation, Tohoku University
    Inventors: Migaku Takahashi, Shin Saito, Tomoyuki Maeda, Akihiko Takeo, Yuzo Sasaki, Ryuji Sakaguchi
  • 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: 20110116189
    Abstract: The present invention relates to a perpendicular magnetic recording medium including at least a backing layer, an orientation control layer, a magnetic recording layer and a protective layer provided on top of a non-magnetic substrate, wherein the orientation control layer is composed of two or more layers including a seed layer and an intermediate layer, formed in that order from the substrate side, and the seed layer is formed of a material containing 5 to 25 atomic % of an element for which, in a phase diagram, the solid solution region with an element having a face-centered cubic structure is not more than 1 atomic %. Also provided is a magnetic recording/reproducing device that includes the magnetic recording medium and a magnetic head for recording and reproducing information on the magnetic recording medium.
    Type: Application
    Filed: September 2, 2008
    Publication date: May 19, 2011
    Applicant: SHOWA DENKO K.K.
    Inventor: Yuzo Sasaki
  • 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: 20110058166
    Abstract: The present invention provides a small spectroscope that has a short response time. A spectroscope according to one embodiment of the present invention includes: a beam deflector that includes an electro-optic crystal, having an electro-optic effect, and paired electrodes used to apply an electric field inside the electro-optic crystal; spectroscopic means for dispersing light output by the beam deflector; and wavelength selection means for selecting light having an arbitrary wavelength from the light dispersed and output by the spectroscopic means.
    Type: Application
    Filed: July 30, 2008
    Publication date: March 10, 2011
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Koichiro Nakamura, Yuzo Sasaki, Kazuo Fujiura, Shogo Yagi
  • Publication number: 20100290155
    Abstract: A method of manufacturing a perpendicular magnetic recording medium is provided which is capable of improving fineness of a particle diameter and vertical orientation of a perpendicular magnetic recording layer, improving corrosion resistance of the magnetic recording medium, and recording and reproducing high-density information.
    Type: Application
    Filed: October 31, 2008
    Publication date: November 18, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato FUKUSHIMA, Gohel KUROKAWA, Yuzo SASAKI
  • Publication number: 20100246060
    Abstract: The present invention relates to a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic layer (SUL), an alignment control layer, a magnetic recording layer and a protective layer formed on the nonmagnetic substrate, wherein the magnetic recording layer is constituted of two or more layers and includes a first magnetic recording layer and a second magnetic recording layer from the nonmagnetic substrate side and, regarding magnetocrystalline anisotropic energy Ku of each magnetic recording layer, the first magnetic recording layer has 4×106 erg/cc or higher and the second magnetic recording layer has 2×106 erg/cc or lower, wherein the first magnetic recording layer is constituted of CoCrPtRu magnetic alloy crystal grains and grain boundaries made of an oxide and the area of grain boundaries is 30% or more based on the entire area in a planar TEM observation of the first magnetic recording layer.
    Type: Application
    Filed: September 30, 2008
    Publication date: September 30, 2010
    Applicant: SHOWA DENKO K.K.
    Inventor: Yuzo Sasaki
  • Publication number: 20100247962
    Abstract: The present invention relates to a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic layer (SUL), an alignment control layer, a magnetic recording layer and a protective layer formed on the nonmagnetic substrate; wherein the magnetic recording layer is constituted of three or more layers and includes a first magnetic recording layer, a second magnetic recording layer and a third magnetic recording layer from the substrate side, and also includes an exchange coupling reduction layer for reducing exchange coupling of both layers between the second magnetic recording layer and the third magnetic recording layer and, regarding magnetocrystalline anisotropic energy Ku of each magnetic recording layer, the first magnetic recording layer has 4×106 erg/cc or higher, the second magnetic recording layer has 2×106 erg/cc or lower and the third magnetic recording layer has 1×106 erg/cc or lower.
    Type: Application
    Filed: October 2, 2008
    Publication date: September 30, 2010
    Inventor: Yuzo Sasaki
  • 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: 20100221579
    Abstract: The present invention relates to a method for manufacturing a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic under layer, an orientation control layer, a magnetic recording layer constituted of two or more layers and a protective layer formed on the nonmagnetic substrate, the method including a step of forming a first magnetic recording layer having a granular structure constituted of ferromagnetic crystal grains and crystal grain boundaries made of a nonmagnetic oxide or nitride on the nonmagnetic substrate side, a step of forming a second magnetic recording layer constituted only of ferromagnetic crystal grains, a step of forming a surface unevenness control layer for decreasing surface unevenness of the first magnetic recording layer located between the first magnetic recording layer and the second magnetic recording layer, and a step of heating the nonmagnetic substrate so as to decrease a surface roughness Ra of the second magnetic recording layer
    Type: Application
    Filed: October 2, 2008
    Publication date: September 2, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Gohei Kurokawa, Yuzo Sasaki