Patents by Inventor Masaaki Futamoto

Masaaki Futamoto 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).

  • Publication number: 20040197607
    Abstract: A double layer perpendicular magnetic recording medium having a high medium S/N ratio at a recording density of 50 Gb/in2 or higher and a magnetic storage apparatus with a lower error rate and excellent reliability are provided. In a perpendicular magnetic recording medium in which a soft magnetic underlayer 12, an intermediate layer 13, and a perpendicular magnetic recording layer 14 are sequentially formed on a substrate 11, the intermediate layer 13 is made to be a non-magnetic amorphous alloy, in which Ni is a main component and Zr is contained, and the soft magnetic underlayer 12 is constituted of ferromagnetic nan-crystals precipitated by annealing.
    Type: Application
    Filed: April 28, 2004
    Publication date: October 7, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Kiwamu Tanahashi, Atsushi Kikugawa, Yukio Honda, Masaaki Futamoto, Akira Ishikawa
  • Publication number: 20040166372
    Abstract: The present invention is directed to-carrying out a high density magnetic recording to a material having a large coercive force by perpendicular magnetic recording head.
    Type: Application
    Filed: December 30, 2003
    Publication date: August 26, 2004
    Inventors: Chiseki Haginoya, Kaori Suzuki, Hisashi Kimura, Masaaki Futamoto, Hideo Matsuyama
  • Patent number: 6770389
    Abstract: To provide an improved perpendicular magnetic recording medium suitable for high density magnetic recording. In a perpendicular magnetic recording medium comprising a perpendicular magnetic layer and protective layer provided on a non-magnetic substrate via a soft magnetic backlayer, a polycrystalline MgO film is inserted between the soft magnetic backlayer and perpendicular magnetic layer.
    Type: Grant
    Filed: April 2, 2003
    Date of Patent: August 3, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Yoshiyuki Hirayama, Yukio Honda, Atsushi Kikukawa
  • Patent number: 6759148
    Abstract: A double layer perpendicular magnetic recording medium having a high medium S/N ratio at a recording density of 50 Gb/in2 or higher and a magnetic storage apparatus with a lower error rate and excellent reliability are obtained with a structure having soft magnetic underlayer 12, an intermediate layer 13 and a perpendicular magnetic recording layer 14 are sequentially formed on a substrate 11. The, intermediate layer 13 is made to be a non-magnetic amorphous alloy, in which Ni is a main component and Zr is contained, and the soft magnetic underlayer 12 is constituted of ferromagnetic nano-crystals precipitated by annealing.
    Type: Grant
    Filed: February 20, 2001
    Date of Patent: July 6, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Kiwamu Tanahashi, Atsushi Kikugawa, Yukio Honda, Masaaki Futamoto, Akira Ishikawa
  • Publication number: 20040090850
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Application
    Filed: November 5, 2003
    Publication date: May 13, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Publication number: 20040072035
    Abstract: The present invention relates to perpendicular magnetic recording media using a ferromagnetic film provided with perpendicular magnetic anisotropy for a recording layer and a magnetic recording apparatus using the media, and the object is to provide the perpendicular magnetic recording media which are excellent in signal to noise ratio (S/N) in a large recording density region, which are stable against thermal fluctuation and which can be easily manufactured, and the magnetic recording apparatus using the media.
    Type: Application
    Filed: August 22, 2003
    Publication date: April 15, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Kazuetsu Yoshida, Masaaki Futamoto, Yoshiyuki Hirayama
  • Patent number: 6716516
    Abstract: Magnetic recording medium includes at least two layers having different magnetic anisotropy constants formed on a substrate and the perpendicular magnetic anisotropy of the second magnetic film of those magnetic films, far from the substrate surface, made equal to or larger than that of the first magnetic film near to the substrate surface, thus improving the magnetic isolation.
    Type: Grant
    Filed: July 26, 2002
    Date of Patent: April 6, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Publication number: 20040062953
    Abstract: A perpendicular magnetic recording medium which has been improved to be suitable for high-density magnetic recording and a magnetic recording apparatus using the medium are provided. The magnetic back film of a dual-layer perpendicular recording medium is caused to be constituted by a plurality of layers, and a keeper layer 17 for keeping perpendicular magnetization and layers 13 and 15 for improving the recording efficiency of a recording head are functionally separated from one another. Further, the magnetization orientations of the soft magnetic films excluding the keeper layer are defined to be in the circumferential direction of the disk, whereby the frequency of occurrence of noise is decreased.
    Type: Application
    Filed: September 22, 2003
    Publication date: April 1, 2004
    Inventors: Masaaki Futamoto, Kazuetsu Yoshida, Yukio Honda, Yoshiyuki Hirayama, Atsushi Kikugawa
  • Patent number: 6686070
    Abstract: A perpendicular magnetic recording medium which has been improved to be suitable for high-density magnetic recording and a magnetic recording apparatus using the medium are provided. The magnetic back film of a dual-layer perpendicular recording medium is caused to be constituted by a plurality of layers, and a keeper layer 17 for keeping perpendicular magnetization and layers 13 and 15 for improving the recording efficiency of a recording head are functionally separated from one another. Further, the magnetization orientations of the soft magnetic films excluding the keeper layer are defined to be in the circumferential direction of the disk, whereby the frequency of occurrence of noise is decreased.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: February 3, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Kazuetsu Yoshida, Yukio Honda, Yoshiyuki Hirayama, Atsushi Kikugawa
  • Patent number: 6687099
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Grant
    Filed: October 15, 2002
    Date of Patent: February 3, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Patent number: 6641901
    Abstract: The present invention relates to perpendicular magnetic recording media using a ferromagnetic film provided with perpendicular magnetic anisotropy for a recording layer and a magnetic recording apparatus using the media, and the object is to provide the perpendicular magnetic recording media which are excellent in signal to noise ratio (S/N) in a large recording density region, which are stable against thermal fluctuation and which can be easily manufactured, and the magnetic recording apparatus using the media.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: November 4, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Kazuetsu Yoshida, Masaaki Futamoto, Yoshiyuki Hirayama
  • Publication number: 20030203189
    Abstract: To provide an improved perpendicular magnetic recording medium suitable for high density magnetic recording.
    Type: Application
    Filed: April 2, 2003
    Publication date: October 30, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Yoshiyuki Hirayama, Yukio Honda, Atsushi Kikukawa
  • Publication number: 20030170497
    Abstract: An ferromagnetic thin film is used to provide a magnetic recording medium whose noise is low and whose S/N value is high. The ferromagnetic thin film as the magnetic film of the magnetic recording medium is such that the fluctuation field of magnetic viscosity at 25° C. at the field strength equal to remanence coercivity or coercivity is not less than 15 oersteds and the coercivity is not less than 2000 oersteds.
    Type: Application
    Filed: March 13, 2003
    Publication date: September 11, 2003
    Inventors: Kazusuke Yamanaka, Tomoo Yamamoto, Yuzuru Hosoe, Nobuyuki Inaba, Yasutaro Uesaka, Masaaki Futamoto, Yoshibumi Matsuda, Kenji Furusawa, Shinji Narishige
  • Patent number: 6613428
    Abstract: A thin film magnetic recording medium including a magnetic layer having a fluctuation field defined as S/Xirr, where S is magnetic viscosity and Xirr is irreversible susceptibility Xirr. The fluctuation field of the magnetic layer is not less than 15 oersteds.
    Type: Grant
    Filed: May 7, 2001
    Date of Patent: September 2, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Kazusuke Yamanaka, Tomoo Yamamoto, Yuzuru Hosoe, Nobuyuki Inaba, Yasutaro Uesaka, Masaaki Futamoto, Yoshibumi Matsuda, Kenji Furusawa, Shinji Narishige
  • Patent number: 6607849
    Abstract: Magnetic recording medium includes at least two layers having different magnetic anisotropy constants formed on a substrate and the perpendicular magnetic anisotropy of the second magnetic film of those magnetic films, far from the substrate surface, made equal to or larger than that of the first magnetic film near to the substrate surface, thus improving the magnetic isolation.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: August 19, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Publication number: 20030143433
    Abstract: The present invention relates to perpendicular magnetic recording media using a ferromagnetic film provided with perpendicular magnetic anisotropy for a recording layer and a magnetic recording apparatus using the media, and the object is to provide the perpendicular magnetic recording media which are excellent in signal to noise ratio (S/N) in a large recording density region, which are stable against thermal fluctuation and which can be easily manufactured, and the magnetic recording apparatus using the media.
    Type: Application
    Filed: January 13, 2003
    Publication date: July 31, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Kazuetsu Yoshida, Masaaki Futamoto, Yoshiyuki Hirayama
  • Patent number: 6592976
    Abstract: Magnetic recording medium includes at least two layers having different magnetic anisotropy constants formed on a substrate and the perpendicular magnetic anisotropy of the second magnetic film of those magnetic films, far from the substrate surface, made equal to or larger than that of the first magnetic film near to the substrate surface, thus improving the magnetic isolation.
    Type: Grant
    Filed: December 20, 2001
    Date of Patent: July 15, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Publication number: 20030117750
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer comprised of an insulating material, a semicondcutor or an antiferromagnetic material against said magnetic layers, and the magnetoresistance effect element has terminals formed with at least on the opposite magnetic layers, respectively, so that a current is sure to be flowed in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Application
    Filed: October 15, 2002
    Publication date: June 26, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Patent number: 6572988
    Abstract: A magnetic recording medium has a magnetic recording film in which the magnitude of saturation magnetization Ms(T=5° K) at 5° K and magnitude of saturation magnetization Ms(T=300° K) at 300° K satisfy: Ms(T=300° K)/Ms(T=5° K)≧0.75. The recording medium enables the high-density recording, and a magnetic recording apparatus using this recording medium can yield a sufficiently high reproduction signal level within the operating temperature range of the apparatus.
    Type: Grant
    Filed: August 30, 1999
    Date of Patent: June 3, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Nobuyuki Inaba, Kazuetsu Yoshida, Kazusuke Yamanaka, Fumiyoshi Kirino, Masaaki Futamoto
  • Patent number: 6562453
    Abstract: To provide an improved perpendicular magnetic recording medium suitable for high density magnetic recording. In a perpendicular magnetic recording medium comprising a perpendicular magnetic layer and protective layer provided on a non-magnetic substrate via a soft magnetic backlayer, a polycrystalline MgO film is inserted between the soft magnetic backlayer and perpendicular magnetic layer.
    Type: Grant
    Filed: July 5, 2000
    Date of Patent: May 13, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Yoshiyuki Hirayama, Yukio Honda, Atsushi Kikukawa