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).

  • Patent number: 6544672
    Abstract: Disclosed is a magnetic recording medium capable of reducing noise and an error rate of the medium. The medium comprises a nonmagnetic substrate; a magnetic layer formed on the surface of the nonmagnetic substrate directly or through a nonmagnetic underlayer; and a protective layer formed on the magnetic layer; wherein the magnetic recording medium satisfies the following relationships: −0.5≦{Hc(1)−Hc(p)}/Hc(1)≦0.3 Hc(1)≧2 kOe 20 G×&mgr;m≦Br(1)×t≦100 G×&mgr;m where Hc(1) indicates a corecivity of the magnetic layer measured in the longitudinal direction; Hc(p) indicates a coercivity of the magnetic layer measured in the perpendicular direction; Br(1) indicates a remanent magnetization of the magnetic layer measured in the longitudinal direction; and “t” indicates a layer thickness of the magnetic layer.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: April 8, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Tomoo Yamamoto, Masukazu Igarashi, Yuzuru Hosoe, Akira Ishikawa
  • Patent number: 6541125
    Abstract: A magnetic recording medium includes a substrate, an underlayer provided on the substrate, a Co alloy magnetic film formed through the underlayer, and a protective film for protecting the magnetic film, wherein the underlayer has a two-layer structure of an lower underlayer contacted with the substrate and an upper underlayer contacted with the Co alloy magnetic film, the upper underlayer is a Co—Crx—My alloy film having a hexagonal close-packed structure, where 25 atomic %≦x+y≦50 atomic %, 0.5 atomic %≦y, nonmagnetic element M is one selected from the group of elements B, Si, Ge, C, Al, P, Ti, V, Nb, Zr, Hf, Mn, Rh, Os, Ir, Re, Pd, Pt, Mo, Ta, W, Ag and Au. Thereby the medium can be increased in its coercive force and can be improved in its thermal stability characteristics.
    Type: Grant
    Filed: December 5, 2001
    Date of Patent: April 1, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Teruaki Takeuchi, Yukio Honda
  • Publication number: 20030053235
    Abstract: An object is to automatically detect the positions of spike noise, create a distribution diagram, and perform pass/fail decisions. The cross-correlation function of the signal waveform from a magnetic head 1 and a reference waveform simulating spike noise is used in extraction of spike noise. The number of peaks in the cross-correlation function exceeding a threshold value is counted, and quantitative evaluation of spike noise is performed.
    Type: Application
    Filed: February 26, 2002
    Publication date: March 20, 2003
    Inventors: Atsushi Kikugawa, Kiwamu Tanahashi, Yukio Honda, Masaaki Futamoto, Yoshiyuki Hirayama
  • Patent number: 6534164
    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: September 7, 2001
    Date of Patent: March 18, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Patent number: 6528149
    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: March 20, 2001
    Date of Patent: March 4, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Kazuetsu Yoshida, Masaaki Futamoto, Yoshiyuki Hirayama
  • Publication number: 20030022025
    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: Application
    Filed: July 26, 2002
    Publication date: January 30, 2003
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Patent number: 6483677
    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: Grant
    Filed: August 20, 2001
    Date of Patent: November 19, 2002
    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
  • Publication number: 20020160233
    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: Application
    Filed: April 22, 2002
    Publication date: October 31, 2002
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Publication number: 20020146592
    Abstract: Disclosed is a magnetic recording medium capable of reducing noise and an error rate of the medium.
    Type: Application
    Filed: March 26, 2002
    Publication date: October 10, 2002
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Tomoo Yamamoto, Masukazu Igarashi, Yuzuru Hosoe, Akira Ishikawa
  • Patent number: 6447936
    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 of the first magnetic film near to the substrate surface.
    Type: Grant
    Filed: June 15, 2000
    Date of Patent: September 10, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Publication number: 20020080520
    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: Application
    Filed: December 20, 2001
    Publication date: June 27, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Patent number: 6403203
    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 of the first magnetic film near to the substrate surface.
    Type: Grant
    Filed: August 24, 1999
    Date of Patent: June 11, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Publication number: 20020068199
    Abstract: A magnetic recording medium includes a substrate, an underlayer provided on the substrate, a Co alloy magnetic film formed through the underlayer, and a protective film for protecting the magnetic film, wherein the underlayer has a two-layer structure of an lower underlayer contacted with the substrate and an upper underlayer contacted with the Co alloy magnetic film, the upper underlayer is a Co—Crx—My alloy film having a hexagonal close-packed structure, where 25 atomic %≦x+y≦50 atomic %, 0.5 atomic % y, nonmagnetic element M is one selected from the group of elements B, Si, Ge, C, Al, P, Ti, V, Nb, Zr, Hf, Mn, Rh, Os, Ir, Re, Pd, Pt, Mo, Ta, W, Ag and Au. Thereby the medium can be increased in its coercive force and can be improved in its thermal stability characteristics.
    Type: Application
    Filed: December 5, 2001
    Publication date: June 6, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Teruaki Takeuchi, Yukio Honda
  • Publication number: 20020055020
    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: Application
    Filed: September 7, 2001
    Publication date: May 9, 2002
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Patent number: 6383667
    Abstract: A magnetic recording medium includes a substrate, an underlayer provided on the substrate, a Co alloy magnetic film formed through the underlayer, and a protective film for protecting the magnetic film, wherein the underlayer has a two-layer structure of an lower underlayer contacted with the substrate and an upper underlayer contacted with the Co alloy magnetic film, the upper underlayer is a Co—Crx—My alloy film having a hexagonal close-packed structure, where 25 atomic %≦x+y≦50 atomic %, 0.5 atomic %≦y, nonmagnetic element M is one selected from the group of elements B, Si, Ge, C, Al, P, Ti, V, Nb, Zr, Hf, Mn, Rh, Os, Ir, Re, Pd, Pt, Mo, Ta, W, Ag and Au. Thereby the medium can be increased in its coercive force and can be improved in its thermal stability characteristics.
    Type: Grant
    Filed: October 7, 1999
    Date of Patent: May 7, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Teruaki Takeuchi, Yukio Honda
  • Publication number: 20020048693
    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.
    Type: Application
    Filed: February 20, 2001
    Publication date: April 25, 2002
    Inventors: Kiwamu Tanahashi, Atsushi Kikugawa, Yukio Honda, Masaaki Futamoto, Akira Ishikawa
  • Publication number: 20020028356
    Abstract: An improved perpendicular magnetic recording medium and an improved magnetic storage apparatus are provided, which are suitable for high speed and high density magnetic recording. A magnetic under layer of a two-layered perpendicular magnetic recording medium includes three layers: a ferromagnetic layer; a non-magnetic layer; and a ferromagnetic layer, wherein the ferromagnetic layers are antiferromagnetically coupled with each other, thereby preventing a magnetic flux from a magnetic wall in a magnetic under layer from entering a read back head.
    Type: Application
    Filed: May 22, 2001
    Publication date: March 7, 2002
    Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
  • Patent number: 6349008
    Abstract: A magnetic recording medium wherein, when the axis of easy magnetization of the magnetic recording medium for magnetically recording information by means of a magnetic head is projected onto a surface of the magnetic recording medium, the axis projected onto the surface of the magnetic recording medium exists so as to be unidirectionally inclined with respect to the direction of a track on which information is to be recorded, whereby, by using the magnetic recording medium, there can be provided a magnetic head and a magnetic read-write apparatus greatly improved in longitudinal recording density.
    Type: Grant
    Filed: October 21, 1998
    Date of Patent: February 19, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Takanobu Takayama, Kiwamu Tanahashi, Kazuetsu Yoshida, Mikio Suzuki, Yoshiyuki Hirayama, Masaaki Futamoto, Yohji Maruyama
  • Publication number: 20020018325
    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: August 20, 2001
    Publication date: February 14, 2002
    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: 20020004151
    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: March 20, 2001
    Publication date: January 10, 2002
    Inventors: Kazuetsu Yoshida, Masaaki Futamoto, Yoshiyuki Hirayama