Patents by Inventor Kazuhiro Nakamoto

Kazuhiro Nakamoto 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: 9245548
    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: Grant
    Filed: January 25, 2008
    Date of Patent: January 26, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Masato Shiimoto, Hiroyuki Katada, Kazuhiro Nakamoto, Hiroyuki Hoshiya
  • Patent number: 8564282
    Abstract: There is provided an angle sensor and angle detection device of high output and high accuracy with a wide operating temperature range. First through eighth sensor units 511, 522, 523, 514, 531, 542, 543 and 534 are produced from spin valve magnetoresistive films that use a self-pinned type ferromagnetic pinned layer comprising two layers of ferromagnetic films that are strongly and anti-ferromagnetically coupled. The respective sensor units are produced via the formation and patterning of thin-films magnetized at angles that differ by 90°, and the formation of insulation films. By using, for the ferromagnetic films, CoFe and FeCo films that have similar Curie temperatures to make the difference in magnetization amount be zero, high immunity to external magnetic fields, a broad adaptive temperature range, and high output are realized.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: October 22, 2013
    Assignee: Hitachi Metals, Ltd.
    Inventors: Hiroyuki Hoshiya, Kenichi Meguroo, Kazuhiro Nakamoto, Yasunori Abe
  • Patent number: 8320073
    Abstract: According to one embodiment, a perpendicular magnetic recording head includes a main pole, wherein a thickness in a down-track direction of the main pole increases moving away from an air bearing surface of the magnetic pole, and wherein a center position in a thickness direction of a portion of the main pole which is exposed at the air bearing surface (the ABS portion) is positioned toward a trailing side of the main pole with respect to a center position in a thickness direction of a portion of the magnetic pole having a greatest cross-sectional area and which is set back from the air bearing surface (the set-back portion). Further embodiments of this magnetic recording head, along with systems thereof and methods of producing magnetic recording heads are also described, according to more embodiments.
    Type: Grant
    Filed: October 25, 2010
    Date of Patent: November 27, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Mikito Sugiyama, Kazuhiro Nakamoto, Kaori Suzuki
  • Patent number: 8174799
    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: Grant
    Filed: July 17, 2008
    Date of Patent: May 8, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hiroyuki Hoshiya, Kenichi Meguro, Katsumi Hoshino, You Sato, Hiroyuki Katada, Kazuhiro Nakamoto
  • Patent number: 8085499
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Grant
    Filed: September 23, 2010
    Date of Patent: December 27, 2011
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20110102936
    Abstract: According to one embodiment, a perpendicular magnetic recording head includes a main pole, wherein a thickness in a down-track direction of the main pole increases moving away from an air bearing surface of the magnetic pole, and wherein a center position in a thickness direction of a portion of the main pole which is exposed at the air bearing surface (the ABS portion) is positioned toward a trailing side of the main pole with respect to a center position in a thickness direction of a portion of the magnetic pole having a greatest cross-sectional area and which is set back from the air bearing surface (the set-back portion). Further embodiments of this magnetic recording head, along with systems thereof and methods of producing magnetic recording heads are also described, according to more embodiments.
    Type: Application
    Filed: October 25, 2010
    Publication date: May 5, 2011
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Mikito Sugiyama, Kazuhiro Nakamoto, Kaori Suzuki
  • Publication number: 20110007417
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Application
    Filed: September 23, 2010
    Publication date: January 13, 2011
    Inventors: Yoshiaki KAWATO, Kazuhiro NAKAMOTO, Hiroyuki HOSHIYA, Yasuyuki OKADA, Masafumi MOCHIZUKI
  • Publication number: 20100327857
    Abstract: There is provided an angle sensor and angle detection device of high output and high accuracy with a wide operating temperature range. First through eighth sensor units 511, 522, 523, 514, 531, 542, 543 and 534 are produced from spin valve magnetoresistive films that use a self-pinned type ferromagnetic pinned layer comprising two layers of ferromagnetic films that are strongly and anti-ferromagnetically coupled. The respective sensor units are produced via the formation and patterning of thin-films magnetized at angles that differ by 90°, and the formation of insulation films. By using, for the ferromagnetic films, CoFe and FeCo films that have similar Curie temperatures to make the difference in magnetization amount be zero, high immunity to external magnetic fields, a broad adaptive temperature range, and high output are realized.
    Type: Application
    Filed: December 3, 2008
    Publication date: December 30, 2010
    Applicant: HITACHI METALS, LTD.
    Inventors: Hiroyuki Hoshiya, Kenichi Meguro, Kazuhiro Nakamoto, Yasunori Abe
  • Patent number: 7813079
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Grant
    Filed: October 21, 2008
    Date of Patent: October 12, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Patent number: 7679862
    Abstract: Embodiments of the invention secure a sufficiently large magnetic field, and deter a protrusion phenomenon of a perpendicular magnetic recording head, causing a problem in implementing a low flying height, while solving problems such as erasure of information in peripheral tracks. In one embodiment, a main pole or a stacked body made up of the main pole, and an auxiliary pole is deposited over an underlayer formed on a substrate so as to be in contact with the underlayer. On top of the main pole or the stacked body, there is deposited a coil, a return pole, and a read element in that order, thereby fabricating a perpendicular magnetic recording head.
    Type: Grant
    Filed: November 14, 2005
    Date of Patent: March 16, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kazuhiro Nakamoto, Kimitoshi Etoh, Masayuki Kurita
  • Patent number: 7599151
    Abstract: Embodiments of the invention provide a magnetic recording and read head which reduces the spread read width in a narrow track having a width of 100 nm or less and shows stable read operation. In one embodiment, a side magnetic shield has a multi-layered structure including non-magnetic separate layers and soft magnetic layers, and the soft magnetic layers are magnetized in opposite directions to reduce a magnetic field induced by the side magnetic shield.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: October 6, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masahiko Hatatani, Chiseki Haginoya, Kenichi Meguro, Kazuhiro Nakamoto
  • Patent number: 7532433
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Grant
    Filed: May 22, 2007
    Date of Patent: May 12, 2009
    Assignee: Hitachi Global Storage Technologies Japa
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Patent number: 7505232
    Abstract: In a side shield structure employed to narrow the effective track, a noise caused by the side shield structure can be reduced. In one embodiment, the side shield is inclined with respect to the film plane to suppress the generation of a magnetic pole in the end portion of the side shield. To this end, the side face of a device is inclined at a desired angle. Further, a reproduction device is formed at two or more angles ?1 and ?2 to improve the track width accuracy.
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: March 17, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Chiseki Haginoya, Masahiko Hatatani, Chiaki Ishakawa, Kenichi Meguro, Kazuhiro Nakamoto, Katsuro Watanabe
  • Publication number: 20090059425
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Application
    Filed: October 21, 2008
    Publication date: March 5, 2009
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • 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: 7456758
    Abstract: To provide a magnetic encoder having high resolution and a high output, and a magnetoresistive sensor for an encoder. A fine sensor having a reduced demagnetization field is produced by: forming a free layer consists of a laminated soft magnetic film in which two soft magnetic layers are coupled in anti-parallel, and setting the width of a sensor unit to 2 ?m to 4 ?m.
    Type: Grant
    Filed: February 20, 2007
    Date of Patent: November 25, 2008
    Assignee: Hitachi Metals, Ltd.
    Inventors: Hiroyuki Hoshiya, Kenichi Meguro, Kazuhiro Nakamoto, Yasunori Abe
  • Publication number: 20080180864
    Abstract: The present invention provides a magnetic sensor suitable for high resolution and having high reliability by achieving stable output even at the occurrence of variations in a gap between a magnetic medium and the magnetic sensor, and a magnetic encoder using the magnetic sensor. The present invention uses a magnetoresistive element having magnetoresistive properties that satisfy the inequation, H10-50<H50-90, where H10-50 represents a magnetic field required for a resistance change from ?R×10% to ?R×50% with respect to a maximum amount of resistance change ?R on a magnetoresitance effect curve, and H50-90 represents a magnetic field required for a resistance change from ?R×50% to ?R×90%.
    Type: Application
    Filed: August 6, 2007
    Publication date: July 31, 2008
    Inventors: Kenichi MEGURO, Hiroyuki HOSHIYA, Kazuhiro NAKAMOTO, Yasuyuki OKADA, Yasunori ABE
  • 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
  • Patent number: 7405905
    Abstract: There is provided a perpendicular magnetic recording and reproducing system in which the overwrite erase ratio of a perpendicular magnetic head has been improved to prevent the deterioration of an overwrite property. In the perpendicular magnetic head, a third magnetic pole composed of a soft magnetic layer is formed on the leading side of a recording magnetic pole via a non-magnetic layer, thereby reducing magnetic interference from magnetization on a medium with the recording magnetic pole and preventing the deterioration of the overwrite property.
    Type: Grant
    Filed: September 8, 2006
    Date of Patent: July 29, 2008
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
  • Patent number: 7400137
    Abstract: The present invention provides a magnetic sensor suitable for high resolution and having high reliability by achieving stable output even at the occurrence of variations in a gap between a magnetic medium and the magnetic sensor, and a magnetic encoder using the magnetic sensor. The present invention uses a magnetoresistive element having magnetoresistive properties that satisfy the inequation, H10?50<H50?90, where H10?50 represents a magnetic field required for a resistance change from ?R×10% to ?R×50% with respect to a maximum amount of resistance change ?R on a magnetoresitance effect curve, and H50?90 represents a magnetic field required for a resistance change from ?R×50% to ?R×90%.
    Type: Grant
    Filed: August 6, 2007
    Date of Patent: July 15, 2008
    Assignee: Hitachi Metals, Ltd.
    Inventors: Kenichi Meguro, Hiroyuki Hoshiya, Kazuhiro Nakamoto, Yasuyuki Okada, Yasunori Abe