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: 7348078
    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: Grant
    Filed: April 12, 2005
    Date of Patent: March 25, 2008
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
  • Publication number: 20080068007
    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: Application
    Filed: February 20, 2007
    Publication date: March 20, 2008
    Inventors: Hiroyuki Hoshiya, Kenichi Meguro, Kazuhiro Nakamoto, Yasunori Abe
  • Publication number: 20070236836
    Abstract: Embodiments in accordance with the present invention provide a thin-film head formed on an AlTiC substrate of a magnetic head slider. A thin-film head include a write element, a read element, a heater, an alumina insulating film that separates the elements and heater from one another, electric wiring films leading to the respective elements, and an alumina protective insulating film that protects all the layered films. For this configuration, in order to maximize a change in a flying height caused by heat dissipated from the heater and minimize a change in the flying height caused by heat dissipation derived from a recording current, the write element is first formed on the AlTiC substrate and the read element is formed on the write element. An adiabatic layer made of a material exhibiting low thermal conductivity may be formed between the write element and the read element and heater.
    Type: Application
    Filed: April 6, 2007
    Publication date: October 11, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masayuki Kurita, Toshiya Shiramatsu, Kazuhiro Nakamoto
  • Publication number: 20070217066
    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 exceeding 10 kOe (oersted), while also modified to suppress remanent magnetic fields occurring immediately after writing operation. In a perpendicular magnetic head comprising a main pole, a return path for supplying a magnetic flux to that 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 has a thickness within 0.5 to 5 nanometers, the high saturation flux density layer has a thickness from 10 to 50 nanometers for suppressing remanent magnetization and preventing erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Application
    Filed: May 22, 2007
    Publication date: September 20, 2007
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Patent number: 7221538
    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 exceeding 10 kOe while suppressing remanent magnetic fields occurring immediately after write operations. The perpendicular magnetic head comprises a main pole, a return path for supplying a magnetic flux to that main pole, and a 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 has a thickness within 0.5 to 5 nanometers, and The high saturation flux density layer has a thickness from 10 to 50.
    Type: Grant
    Filed: August 20, 2003
    Date of Patent: May 22, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20070002492
    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: Application
    Filed: September 8, 2006
    Publication date: January 4, 2007
    Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
  • Patent number: 7158351
    Abstract: A magnetic recording head includes an upper shield layer, a lower shield layer, a magnetoresistive film interposed between the upper shield layer and the lower shield layer, and a pair of leads electrically coupled to the magnetoresistive film, in which a pair of side shield layers constituted by portions of the upper shield layer is formed on both sides of the magnetoresistive film, and a spacing between each side shield layer and the magnetoresistive film is formed to be narrower than twice of a spacing between the upper shield layer and the lower shield layer, thereby a side reading amount can be made smaller than a conventional side reading value determined from the spacing between the upper and lower shield layers and a magnetic spacing between the head and a medium.
    Type: Grant
    Filed: August 3, 2005
    Date of Patent: January 2, 2007
    Assignee: Hitachi Global Storage Technologies
    Inventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa
  • Patent number: 7145750
    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: January 3, 2003
    Date of Patent: December 5, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
  • Patent number: 7054106
    Abstract: Disclosed herein is a magnetic head for perpendicular recording in which the main magnetic pole has reduced remanent magnetization and is less liable to cause erasure after recording. These characteristic properties were realized by constructing the magnetic head such that the recording magnetic pole and the yoke are separate from each other and the main magnetic pole is formed from a material with a high saturation magnetic flux density and the yoke is formed from a material having a negative magnetostriction constant.
    Type: Grant
    Filed: January 31, 2003
    Date of Patent: May 30, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Kazue Kudo, Yoshiaki Kawato, Kazuhiro Nakamoto, Nobuo Yoshida, Kimitoshi Etoh
  • Publication number: 20060103982
    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: Application
    Filed: November 14, 2005
    Publication date: May 18, 2006
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kazuhiro Nakamoto, Kimitoshi Etoh, Masayuki Kurita
  • Publication number: 20060018055
    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: Application
    Filed: June 24, 2005
    Publication date: January 26, 2006
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Chiseki Haginoya, Masahiko Hatatani, Chiaki Ishikawa, Kenichi Meguro, Kazuhiro Nakamoto, Katsuro Watanabe
  • Publication number: 20050264948
    Abstract: A magnetic recording head includes an upper shield layer, a lower shield layer, a magnetoresistive film interposed between the upper shield layer and the lower shield layer, and a pair of leads electrically coupled to the magnetoresistive film, in which a pair of side shield layers constituted by portions of the upper shield layer is formed on both sides of the magnetoresistive film, and a spacing between each side shield layer and the magnetoresistive film is formed to be narrower than twice of a spacing between the upper shield layer and the lower shield layer, thereby a side reading amount can be made smaller than a conventional side reading value determined from the spacing between the upper and lower shield layers and a magnetic spacing between the head and a medium.
    Type: Application
    Filed: August 3, 2005
    Publication date: December 1, 2005
    Inventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa
  • Patent number: 6967823
    Abstract: A magnetic recording head includes an upper shield layer, a lower shield layer, a magnetoresistive film interposed between the upper shield layer and the lower shield layer, and a pair of leads electrically coupled to the magnetoresistive film, in which a pair of side shield layers constituted by portions of the upper shield layer is formed on both sides of the magnetoresistive film, and a spacing between each side shield layer and the magnetoresistive film is formed to be narrower than twice of a spacing between the upper shield layer and the lower shield layer, thereby a side reading amount can be made smaller than a conventional side reading value determined from the spacing between the upper and lower shield layers and a magnetic spacing between the head and a medium.
    Type: Grant
    Filed: June 4, 2003
    Date of Patent: November 22, 2005
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa
  • Publication number: 20050214587
    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: April 12, 2005
    Publication date: September 29, 2005
    Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
  • Patent number: 6926974
    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: Grant
    Filed: May 22, 2001
    Date of Patent: August 9, 2005
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
  • Publication number: 20050157431
    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: Application
    Filed: October 29, 2004
    Publication date: July 21, 2005
    Applicant: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Masahiko Hatatani, Chiseki Haginoya, Kenichi Meguro, Kazuhiro Nakamoto
  • Publication number: 20040150912
    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 exceeding 10 kOe (oersted), while also modified to suppress remanent magnetic fields occurring immediately after writing operation. In a perpendicular magnetic head comprising a main pole, a return path for supplying a magnetic flux to that 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 has a thickness within 0.5 to 5 nanometers, the high saturation flux density layer has a thickness from 10 to 50 nanometers for suppressing remanent magnetization and preventing erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Application
    Filed: August 20, 2003
    Publication date: August 5, 2004
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20040100737
    Abstract: A magnetic recording head includes an upper shield layer, a lower shield layer, a magnetoresistive film interposed between the upper shield layer and the lower shield layer, and a pair of leads electrically coupled to the magnetoresistive film, in which a pair of side shield layers constituted by portions of the upper shield layer is formed on both sides of the magnetoresistive film, and a spacing between each side shield layer and the magnetoresistive film is formed to be narrower than twice of a spacing between the upper shield layer and the lower shield layer, thereby a side reading amount can be made smaller than a conventional side reading value determined from the spacing between the upper and lower shield layers and a magnetic spacing between the head and a medium.
    Type: Application
    Filed: June 4, 2003
    Publication date: May 27, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa
  • Patent number: 6731478
    Abstract: A slider includes an air-introducing plane, a groove, an air flow-out end, and a thin-film magnetic head formed on the air flow-out end. The thin-film magnetic head includes a magnetoresistive effect type film which includes a first ferromagnetic film having a direction of magnetization which is changeable, an antiferromagnetic film, a second ferromagnetic film having a direction of magnetization which is fixed, and a non-magnetic conductive film disposed between the first ferromagnetic film and the second ferromagnetic film. The thin-film magnetic head further includes a pair of magnetic domain control films respectively arranged at ends of the magnetoresistive effect type film, and a pair of electrodes directly overlapping both end domains of the magnetoresistive effect type film. A spacing between the electrodes is narrower than a spacing between the magnetic domain control films.
    Type: Grant
    Filed: March 28, 2003
    Date of Patent: May 4, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Nakamoto, Yoshiaki Kawato
  • Publication number: 20040037002
    Abstract: Disclosed herein is a magnetic head for perpendicular recording in which the main magnetic pole has reduced remanent magnetization and is less liable to cause erasure after recording. These characteristic properties were realized by constructing the magnetic head such that the recording magnetic pole and the yoke are separate from each other and the main magnetic pole is formed from a material with a high saturation magnetic flux density and the yoke is formed from a material having a negative magnetostriction constant.
    Type: Application
    Filed: January 31, 2003
    Publication date: February 26, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Kazue Kudo, Yoshiaki Kawato, Kazuhiro Nakamoto, Nobuo Yoshida, Kimitoshi Etoh