Patents by Inventor Hiroyuki Katada

Hiroyuki Katada 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: 20090207531
    Abstract: A magnetic recording read head is provided capable of achieving high reproduction output, resolution, and SNR, even at a high linear density. There is also provided a magnetic recording and reproducing device capable of achieving sufficient error bit rate. The magnetic recording read head includes a differential read head and a write head. The differential read head has a multilayer structure formed by laminating a first magnetoresistive sensor having a first free layer, a differential gap layer, and a second magnetoresistive sensor having a second free layer. Outside the multilayer structure, a pair of electrodes and a pair of magnetic shields are provided respectively. A ratio (Gl/bl) of an inside distance (Gl) between the first and second free layers to a bit length (bl) is set to 0.6 or more and 1.6 or less.
    Type: Application
    Filed: February 4, 2009
    Publication date: August 20, 2009
    Inventors: Masato SHIIMOTO, Takeshi Nakagawa, Hiroyuki Katada, Naoto Ito, Kenichi Meguro
  • Publication number: 20090046394
    Abstract: Embodiments of the present invention help to prevent a head characteristic from being deteriorated by re-deposition or damage which occurs when a sensor film is etched, a track width is narrowed, and the head characteristic is stabilized. According to one embodiment, when it is assumed that the thickness of the sensor film on an air bearing surface is T, and a distance between an end of a medium layer that is interposed between a free layer and a pinned layer which comprise the sensor film and an end of the sensor film lowest portion, a relationship of 1.2×T?x?2.5×T is satisfied, and the ends of a pair of magnetic films which are in contact with both sides in the track-width direction through an insulator do not exist in the track central portion from the free layer end.
    Type: Application
    Filed: January 29, 2008
    Publication date: February 19, 2009
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Satoru Okamoto, Koji Okazaki, Shuuichi Kojima, Nobuo Yoshida, Katsuro Watanabe, Hiroyuki Katada
  • Publication number: 20090034135
    Abstract: Embodiments of the present invention help to provide a single element type differential magnetoresistive magnetic head capable of achieving high resolution and high manufacturing stability. According to one embodiment, a magnetoresistive layered film is formed by stacking an underlayer film, an antiferromagnetic film, a ferromagnetic pinned layer, a non-magnetic intermediate layer, a soft magnetic free layer, a long distance antiparallel coupling layered film, and a differential soft magnetic free layer. The long distance antiparallel coupling layered film exchange-couples the soft magnetic free layer and the differential soft magnetic free layer in an antiparallel state with a distance of about 3 nanometers through 20 nanometers. By manufacturing the single element type differential magnetoresistive magnetic head using the magnetoresistive layered film, it becomes possible to achieve the high resolution and the high manufacturing stability without spoiling the GMR effect.
    Type: Application
    Filed: July 17, 2008
    Publication date: February 5, 2009
    Applicant: Hitachi Global Storage Technologies
    Inventors: Hiroyuki Hoshiya, Kenichi Meguro, Katsumi Hoshino, Yo Sato, Hiroyuki Katada, Kazuhiro Nakamoto
  • Patent number: 7440241
    Abstract: A magnetoresistive head and a fabricating method thereof accomplishing high read sensitivity and excellent linear response with low noise even if track width narrowing makes progress are provided. In one embodiment, using a magnetoresistive film having a laminated body of a pinned layer/an intermediate layer/a free layer/a separate layer/a first ferromagnetic layer/a 90-degree magnetic interlayer coupling layer/a second ferromagnetic layer, and the magnetizations of both the pinned layer and the second ferromagnetic layer are fixed nearly in the direction along the sensor height. On the other hand, the magnetizations of the first ferromagnetic layer and the second ferromagnetic layer have an interlayer interaction being directed in nearly orthogonal directions to each other through the 90-degree magnetic interlayer coupling layer, and the first ferromagnetic layer has a magnetization directed nearly in the direction along the track width in zero external magnetic field.
    Type: Grant
    Filed: October 3, 2005
    Date of Patent: October 21, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Katsumi Hoshino, Hiroyuki Hoshiya, Hiroyuki Katada, Kenichi Meguro
  • Publication number: 20080182133
    Abstract: Embodiments of the present invention help to reduce mag-noise in a magnetoresistive head without deterioration in reproduced output and improve the signal/noise ratio (SNR) of the magnetoresistive head. According to one embodiment, the magnetoresistive head uses a synthetic ferri free layer and it is arranged such that the magnetic field which is applied to an end of a free layer with smaller film thickness and saturation magnetization in the track width direction by a coupling field is larger than the magnetic field which is applied to it by a bias layer.
    Type: Application
    Filed: January 25, 2008
    Publication date: July 31, 2008
    Inventors: Masato Shiimoto, Hiroyuki Katada, Kazuhiro Nakamoto, Hiroyuki Hoshiya
  • Publication number: 20080055791
    Abstract: Embodiments of the present invention aim suppress the generation of spin torque noise in a current perpendicular to plane magnetoresistive head. According to one embodiment, when sensing current is applied to a current perpendicular to plane magnetoresistive head from a free layer toward a first pinned layer, a configuration wherein the relative angle between the magnetization of a second pinned layer and the magnetization of the free layer is in the range of 70 to 80 degrees is used. Further, when sensing current is applied to a current perpendicular to plane magnetoresistive head from a first pinned layer toward a free layer, a configuration wherein the relative angle between the magnetization of a second pinned layer and the magnetization of the free layer is in the range of 100 to 110 degrees is used.
    Type: Application
    Filed: August 3, 2007
    Publication date: March 6, 2008
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hiroyuki Katada, Hiroyuki Hoshiya
  • Publication number: 20070188934
    Abstract: Embodiments in accordance with the present invention provide a method of manufacturing a magneto-resistive head which can realize high sensitivity and good linear response characteristics with low noise even if a track width becomes narrower. A uniaxial anisotropy unaffected by annealing which is due to the orientation of the crystal grain growth direction, is induced in a magnetic layer. The free magnetic layer has the synthetic antiferromagnetic construction: first magnetic layer/interlayer antiferromagnetic coupling layer/second magnetic layer, the magnitude of the antiferromagnetic coupling is adjusted, and linear response characteristics are obtained even if a longitudinal biasing field applying mechanism is not provided.
    Type: Application
    Filed: January 24, 2007
    Publication date: August 16, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kenichi Meguro, Hiroyuki Katada, Katsumi Hoshino, Hiroyuki Hoshiya
  • Publication number: 20070091511
    Abstract: A spin-valve type magnetic head which has sufficiently high output is provided. In one embodiment, a structure in which high output coexists with high stability is achieved by letting a GMR-effect and a current-path-confinement effect manifest themselves at the same time in a GMR-screen layer consisting of a ferromagnetic metal spike-like part and a half-covering oxide layer.
    Type: Application
    Filed: October 19, 2006
    Publication date: April 26, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hiroyuki Hoshiya, Katsumi Hoshino, Kenichi Meguro, Yo Sato, Hiroyuki Katada
  • Publication number: 20060103991
    Abstract: A magnetoresistive head and a fabricating method thereof accomplishing high read sensitivity and excellent linear response with low noise even if track width narrowing makes progress are provided. In one embodiment, using a magnetoresistive film having a laminated body of a pinned layer/an intermediate layer/a free layer/a separate layer/a first ferromagnetic layer/a 90-degree magnetic interlayer coupling layer/a second ferromagnetic layer, and the magnetizations of both the pinned layer and the second ferromagnetic layer are fixed nearly in the direction along the sensor height. On the other hand, the magnetizations of the first ferromagnetic layer and the second ferromagnetic layer have an interlayer interaction being directed in nearly orthogonal directions to each other through the 90-degree magnetic interlayer coupling layer, and the first ferromagnetic layer has a magnetization directed nearly in the direction along the track width in zero external magnetic field.
    Type: Application
    Filed: October 3, 2005
    Publication date: May 18, 2006
    Applicant: Hitachi Global Storage Technologies
    Inventors: Katsumi Hoshino, Hiroyuki Hoshiya, Hiroyuki Katada, Kenichi Meguro
  • Patent number: D271200
    Type: Grant
    Filed: May 6, 1981
    Date of Patent: November 1, 1983
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Kozo Kawasaki, Hiroyuki Katada
  • Patent number: D281604
    Type: Grant
    Filed: February 1, 1983
    Date of Patent: December 3, 1985
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Kozo Kawasaki, Hiroyuki Katada