Patents by Inventor Tokuho Takagaki

Tokuho Takagaki 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: 7159303
    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: March 9, 2006
    Date of Patent: January 9, 2007
    Assignee: Hitachi Global Storage Technologies, 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: 20060152862
    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: March 9, 2006
    Publication date: July 13, 2006
    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: 7054120
    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: November 5, 2003
    Date of Patent: May 30, 2006
    Assignee: Hitachi Global Storage Technologies Japan, 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: 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
  • 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
  • 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: 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: 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
  • Patent number: 6278593
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semicondutor or an antiferromagnetic material against the magnetic layers, and the magneto-resistance 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: December 21, 1999
    Date of Patent: August 21, 2001
    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: 6011674
    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-denisity recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Grant
    Filed: April 2, 1996
    Date of Patent: January 4, 2000
    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: 5879569
    Abstract: To provide a magnetic disk excellent in floating and sliding characteristics in a low floating area. A magnetic disk having a feature that variations in the height of the projections on each surface of protective films in floating ensured areas on both sides of the magnetic disk are .+-.15%, and a magnetic disk device on which the magnetic disk is mounted.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: March 9, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Matsumoto, Hiroshi Yashiki, Yoichi Inomata, Tatsuya Yoneda, Kazuhiko Tsutsumi, Noriyuki Shige, Tokuho Takagaki
  • Patent number: 5736235
    Abstract: A magnetic recording medium, its fabrication method, and a magnetic recording apparatus in which both saturation induction and coercive force of a magnetic film is made high as they are near a surface of the recording medium. A high density information recording can be made higher than 50 kFCI in linear recording density even for spacing around 0.2 .mu.m.
    Type: Grant
    Filed: August 6, 1991
    Date of Patent: April 7, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Yoshibumi Matsuda, Masaaki Futamoto, Yoshinori Miyamura, Tokuho Takagaki, Hisashi Takano, Fumio Kugiya, Takeshi Nakao, Kyo Akagi, Mikio Suzuki, Hirotsugu Fukuoka, Takayuki Munemoto
  • Patent number: 5726837
    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: October 24, 1994
    Date of Patent: March 10, 1998
    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: 5587235
    Abstract: A magnetic recording medium and magnetic recording apparatus which can provide a high output level and a low noise level are disclosed. A magnetic recording medium includes a multilayer structure of magnetic alloy thin films containing Co, and at least one paramagnetic intermediate region or oxygen-rich region disposed between the magnetic layers. The intermediate region reduces the magnetic interaction between the magnetic layers without the degradation of crystallinity of the magnetic layers. As a result, a magnetic recording medium having such a structure shows low noise performance and a high recording density.
    Type: Grant
    Filed: February 8, 1994
    Date of Patent: December 24, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Suzuki, Naoki Kodama, Takao Yonekawa, Tokuho Takagaki, Naoto Endo, Katsuo Abe, Tsuneo Suganuma
  • Patent number: 5568331
    Abstract: A method and device of head positioning in an information recording/reading device in which a magnetic recording medium with data tracks for recording information thereon is provided and a magnetic head is positioned on the data track to record/read out the information, wherein a data signal is recorded in the data recording layer of said recording medium, a servo signal is recorded in the servo signal recording layer located below said data signal recording layer, said data signal is read out using a data magnetic head whereas said servo signal is read out using a servo magnetic head, and the frequency of said servo signal is within the range of the gap-null frequency of said data magnetic head whereas the frequency of said data signal is within the range of the gap-null frequency of said servo magnetic head, and said magnetic head is positioned on the data track on the basis of said servo signal.
    Type: Grant
    Filed: October 25, 1990
    Date of Patent: October 22, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Kyo Akagi, Masaaki Futamoto, Fumio Kugiya, Yoshinori Miyamura, Hisashi Takano, Yoshibumi Matsuda, Mikio Suzuki, Takeshi Nakao, Takayuki Munemoto, Hirotsugu Fukuoka, Makoto Aihara, Tokuho Takagaki, Hajime Aoi, Yosuke Seo
  • Patent number: 5390061
    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 magneto-resistance 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: June 5, 1991
    Date of Patent: February 14, 1995
    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: 5325244
    Abstract: A magnetic recording data storage system includes a magnetic recording medium having pits formed therein, the pits defining recording tracks on the magnetic recording medium and being arranged in a staggered manner relative to respective center lines of the recording tracks, a magnetic head including an inductive element for recording data on the recording tracks and a magnetoresistive element for reproducing data from the recording tracks, one of (1) a unit for magnetically producing a signal from the pits, and (2) an optical unit for optically producing a signal from the pits, the optical unit including a laser for illuminating the pits, servo means for positioning the head on the recording tracks based on the signal produced from the pits, the servo means including a dual-stage actuator including a rough movement portion and a fine movement portion.
    Type: Grant
    Filed: February 28, 1992
    Date of Patent: June 28, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Hisashi Takano, Kyo Akagi, Mikio Suzuki, Yoshibumi Matsuda, Takeshi Nakao, Yoshinori Miyamura, Fumio Kugiya, Masaaki Futamoto, Hideki Sawaguchi, Nobuyuki Inaba, Takayuki Munemoto, Kenji Mori, Hirotsugu Fukuoka, Tokuho Takagaki
  • Patent number: 4950548
    Abstract: The present invention relates to a magnetic recording medium for a magnetic disk unit or the like and, more particularly, to a magnetic recording medium having its recording layer made of a magnetic alloy film with uniform magnetic characteristics. The present magnetic recording medium comprises a non-magnetic substrate, at least two sputtered layers of chromium thin film having a bow-like columnar structure which chromium thin film is laminated on the substrate, another sputtered layer of a magnetic alloy thin film laminated on the chromium thin film, and a protective layer laminated on the magnetic alloy thin film. The present invention is effective in reducing modulation of regenerative output relatively independent of a texture roughness of the substrate.
    Type: Grant
    Filed: May 23, 1989
    Date of Patent: August 21, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Kenji Furusawa, Katsuo Abe, Hiroyuki Kataoka, Tokuho Takagaki, Yoshihiro Shiroishi, Norikazu Tsumita