Patents by Inventor Toyoji Ataka

Toyoji Ataka 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: 9659592
    Abstract: A perpendicular magnetic recording medium exhibits reduced noise and improved performance in such measures as SN ratio, and can realize high magnetic recording densities. In the perpendicular magnetic recording medium, at least a first nonmagnetic intermediate layer, second nonmagnetic intermediate layer, and magnetic recording layer are stacked in order on a nonmagnetic substrate. The first nonmagnetic intermediate layer is formed from a CoCrRuW alloy, and the second nonmagnetic intermediate layer is formed from an Ru-base alloy.
    Type: Grant
    Filed: May 1, 2012
    Date of Patent: May 23, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Toyoji Ataka, Shunji Takenoiri, Sadayuki Watanabe, Hirohisa Oyama, Yasuaki Hozumi, Satoshi Takahashi
  • Publication number: 20130209836
    Abstract: A perpendicular magnetic recording medium exhibits reduced noise and improved performance in such measures as SN ratio, and can realize high magnetic recording densities. In the perpendicular magnetic recording medium, at least a first nonmagnetic intermediate layer, second nonmagnetic intermediate layer, and magnetic recording layer are stacked in order on a nonmagnetic substrate. The first nonmagnetic intermediate layer is formed from a CoCrRuW alloy, and the second nonmagnetic intermediate layer is formed from an Ru-base alloy.
    Type: Application
    Filed: May 1, 2012
    Publication date: August 15, 2013
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Toyoji Ataka, Shunji Takenoiri, Sadayuki Watanabe, Hirohisa Oyama, Yasuaki Hozumi, Satoshi Takahashi
  • Publication number: 20080044688
    Abstract: A high-recording-density magnetic recording medium and a method of its manufacture can achieve a high OR with only a small reduction in Hcr. The magnetic recording medium has a nonmagnetic substrate and a first seed layer, a second seed layer, a first underlayer, a second underlayer, and a magnetic recording layer formed on the substrate in this order. The first seed layer can be a single layer or a plurality of layers made of at least one material selected from the group consisting of Ni—Ti alloys, Cr—Al alloys, Cr—Ta alloys, and Cr—Ti alloys. The second seed layer can be a single layer or a plurality of layers made of at least one material selected from the group consisting of Ni—W alloys, Ni—Ru—W alloys, and Co—W alloys. The first underlayer can be a single layer or a plurality of layers made of a Cr—Ru alloy. The second underlayer can be a single layer or a plurality of layers made of a Cr alloy comprising Cr and at least one element selected from the group consisting of Mo, B, Ti, and W.
    Type: Application
    Filed: March 7, 2007
    Publication date: February 21, 2008
    Applicant: FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD.
    Inventors: Tuqiang Li, Manabu Shimosato, Toyoji Ataka, Hiromi Ono, Kenichiro Soma, Hiroyuki Uwazumi, Souta Matsuo
  • Publication number: 20060115686
    Abstract: A high-density magnetic recording medium uses a nonmetallic substrate, while still providing high in-plane magnetic anisotropy and remanent coercivity. Such a medium can be formed by depositing a seed layer on a textured surface of the nonmetallic substrate in a gas mixture containing oxygen or nitrogen and an inert gas, while controlling the oxygen concentration or nitrogen concentration, and subsequently exposing the surface of the seed layer to oxygen or nitrogen.
    Type: Application
    Filed: January 17, 2006
    Publication date: June 1, 2006
    Applicant: Fuji Electric Co., Ltd.
    Inventors: Toyoji Ataka, Satoru Nakamura, Katsuya Masuda, Ryoichi Kadota, Yuji Ando
  • Patent number: 7014882
    Abstract: A high-density magnetic recording medium uses a nonmetallic substrate, while still providing high in-plane magnetic anisotropy and remanent coercivity. Such a medium can be formed by depositing a seed layer on a textured surface of the nonmetallic substrate in a gas mixture containing oxygen or nitrogen and an inert gas, while controlling the oxygen concentration or nitrogen concentration, and subsequently exposing the surface of the seed layer to oxygen or nitrogen.
    Type: Grant
    Filed: March 13, 2003
    Date of Patent: March 21, 2006
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Toyoji Ataka, Satoru Nakamura, Katsuya Masuda, Ryoichi Kadota, Yuji Ando
  • Patent number: 6849164
    Abstract: A magnetic recording medium and method of manufacturing the same including directly texturing a surface of a non-magnetic substrate made of a glass material to form circular concentric grooves thereon, forming a seed layer on the non-magnetic substrate, forming an under layer on the seed layer, forming a magnetic layer on the under layer, and forming a protective layer on the magnetic layer. A ratio of an in-plane remanent magnetization in a circumferential direction of the magnetic recording medium to an in-plane remanent magnetization in a radial direction of the magnetic recording medium is equal to or greater than 1.05.
    Type: Grant
    Filed: May 10, 2002
    Date of Patent: February 1, 2005
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Toyoji Ataka, Yuji Ando, Satoru Nakamura, Katsuya Masuda, Manabu Shimosato
  • Patent number: 6764721
    Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.
    Type: Grant
    Filed: October 20, 2003
    Date of Patent: July 20, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
  • Publication number: 20040072037
    Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.
    Type: Application
    Filed: October 20, 2003
    Publication date: April 15, 2004
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
  • Publication number: 20040009372
    Abstract: A high-density magnetic recording medium uses a nonmetallic substrate, while still providing high in-plane magnetic anisotropy and remanent coercivity. Such a medium can be formed by depositing a seed layer on a textured surface of the nonmetallic substrate in a gas mixture containing oxygen or nitrogen and an inert gas, while controlling the oxygen concentration or nitrogen concentration, and subsequently exposing the surface of the seed layer to oxygen or nitrogen.
    Type: Application
    Filed: March 13, 2003
    Publication date: January 15, 2004
    Inventors: Toyoji Ataka, Satoru Nakamura, Katsuya Masuda, Ryoichi Kadota, Yuji Ando
  • Patent number: 6667117
    Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.
    Type: Grant
    Filed: March 8, 2001
    Date of Patent: December 23, 2003
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
  • Publication number: 20030012983
    Abstract: A magnetic recording medium and method of manufacturing the same including directly texturing a surface of a non-magnetic substrate made of a glass material to form circular concentric grooves thereon, forming a seed layer on the non-magnetic substrate, forming an under layer on the seed layer, forming a magnetic layer on the under layer, and forming a protective layer on the magnetic layer. A ratio of an in-plane remanent magnetization in a circumferential direction of the magnetic recording medium to an in-plane remanent magnetization in a radial direction of the magnetic recording medium is equal to or greater than 1.05.
    Type: Application
    Filed: May 10, 2002
    Publication date: January 16, 2003
    Inventors: Toyoji Ataka, Yuji Ando, Satoru Nakamura, Katsuya Masuda, Manabu Shimosato
  • Publication number: 20010038932
    Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.
    Type: Application
    Filed: March 8, 2001
    Publication date: November 8, 2001
    Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
  • Patent number: 6037069
    Abstract: A magnetic recording medium has a non-magnetic metal base layer formed on a non-magnetic base and supporting a magnetic layer thereon. The non-magnetic metal base layer includes two or more base layers including at least one first base layer each having an anisotropic magnetic characteristic in which a coercive force in a circumferential direction of the magnetic recording medium is higher than a coercive force in a radial direction of the medium, and at least one second base layer each having an anisotropic magnetic characteristic in which the coercive force in the circumferential direction is lower than the coercive force in the radial direction.
    Type: Grant
    Filed: May 30, 1996
    Date of Patent: March 14, 2000
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Toyoji Ataka, Keiji Okubo, Masashi Kanamori
  • Patent number: 5939202
    Abstract: A magnetic recording medium is provided which includes a non-magnetic base, and a non-magnetic metal base layer, a magnetic layer, and a protective layer, which are laminated in the order of description on the non-magnetic base, wherein the non-magnetic metal base layer is formed from an alloy film in which at least one element selected from the group consisting of W, Ta, Hf, Mo, Cr, Zr and Nb is added to NiAl.
    Type: Grant
    Filed: October 7, 1997
    Date of Patent: August 17, 1999
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Toyoji Ataka, Keiji Ohkubo, Noboru Kurata, Naoki Takizawa, Kazuo Enomoto
  • Patent number: 5891514
    Abstract: In a method for manufacturing a magnetic recording medium, a non-metallic metal base layer, a ferromagnetic alloy thin-film magnetic layer and a protective layer are successively laminated on a non-magnetic substrate. The ferromagnetic alloy thin-film magnetic layer consists of a first magnetic layer and a second magnetic layer. In the method of the present invention, the first magnetic layer is formed in an atmosphere containing an Ar gas, and the second magnetic layer is formed in an atmosphere containing a mixture of Ar and N.sub.2 gases.
    Type: Grant
    Filed: November 17, 1997
    Date of Patent: April 6, 1999
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Toyoji Ataka, Keiji Ohkubo
  • Patent number: 5576098
    Abstract: A thin film magnetic head includes an upper magnetic core film and a lower magnetic core film laminated one on another through a magnetic gap layer. The upper and lower magnetic core films are multilayer thin films, respectively, each of which is composed of a plurality of magnetic thin film layers and a plurality of non-magnetic thin film layers, alternately laminated one on another. The magnetic core films and have single domain structures, respectively, and the use of such magnetic core films realizes a thin film magnetic head having high permeability at high frequencies and improved high frequency characteristics and attains high recording density.
    Type: Grant
    Filed: July 6, 1993
    Date of Patent: November 19, 1996
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yuko Arimoto, Takabumi Fumoto, Keiji Okubo, Osamu Saito, Toyoji Ataka, Hisashi Yamasaki
  • Patent number: 5503686
    Abstract: A magnetic recording head that includes a combined IN element and an MR element is heat treated under two types of magnetic fields. A rotating magnetic field, having a first magnetic field intensity, is applied for a time while the magnetic recording head is at an elevated temperature. Then, part-way during cooling of the magnetic head, the rotating magnetic field is replaced by a direct (non-rotating) magnetic field having a second magnetic field intensity. The second magnetic field intensity is lower than the first magnetic field intensity, whereby the properties of both the IN element and the MR element are maintained at high values.
    Type: Grant
    Filed: March 13, 1995
    Date of Patent: April 2, 1996
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yuko Okamura, Keiji Ohkubo, Osamu Saito, Toyoji Ataka