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).
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Patent number: 7405905Abstract: 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: GrantFiled: September 8, 2006Date of Patent: July 29, 2008Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
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Patent number: 7400137Abstract: 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: GrantFiled: August 6, 2007Date of Patent: July 15, 2008Assignee: Hitachi Metals, Ltd.Inventors: Kenichi Meguro, Hiroyuki Hoshiya, Kazuhiro Nakamoto, Yasuyuki Okada, Yasunori Abe
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Patent number: 7348078Abstract: 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: GrantFiled: April 12, 2005Date of Patent: March 25, 2008Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
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Publication number: 20080068007Abstract: 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: ApplicationFiled: February 20, 2007Publication date: March 20, 2008Inventors: Hiroyuki Hoshiya, Kenichi Meguro, Kazuhiro Nakamoto, Yasunori Abe
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Publication number: 20070236836Abstract: 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: ApplicationFiled: April 6, 2007Publication date: October 11, 2007Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Masayuki Kurita, Toshiya Shiramatsu, Kazuhiro Nakamoto
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Publication number: 20070217066Abstract: 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: ApplicationFiled: May 22, 2007Publication date: September 20, 2007Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Patent number: 7221538Abstract: 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: GrantFiled: August 20, 2003Date of Patent: May 22, 2007Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Publication number: 20070002492Abstract: 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: ApplicationFiled: September 8, 2006Publication date: January 4, 2007Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
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Patent number: 7158351Abstract: 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: GrantFiled: August 3, 2005Date of Patent: January 2, 2007Assignee: Hitachi Global Storage TechnologiesInventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa
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Patent number: 7145750Abstract: 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: GrantFiled: January 3, 2003Date of Patent: December 5, 2006Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Hisashi Kimura, Kazuhiro Nakamoto, Yoshiaki Kawato, Nobuo Yoshida
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Patent number: 7054106Abstract: 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: GrantFiled: January 31, 2003Date of Patent: May 30, 2006Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Kazue Kudo, Yoshiaki Kawato, Kazuhiro Nakamoto, Nobuo Yoshida, Kimitoshi Etoh
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Publication number: 20060103982Abstract: 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: ApplicationFiled: November 14, 2005Publication date: May 18, 2006Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Kazuhiro Nakamoto, Kimitoshi Etoh, Masayuki Kurita
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Publication number: 20060018055Abstract: 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: ApplicationFiled: June 24, 2005Publication date: January 26, 2006Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Chiseki Haginoya, Masahiko Hatatani, Chiaki Ishikawa, Kenichi Meguro, Kazuhiro Nakamoto, Katsuro Watanabe
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Publication number: 20050264948Abstract: 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: ApplicationFiled: August 3, 2005Publication date: December 1, 2005Inventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa
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Patent number: 6967823Abstract: 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: GrantFiled: June 4, 2003Date of Patent: November 22, 2005Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa
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Publication number: 20050214587Abstract: 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: ApplicationFiled: April 12, 2005Publication date: September 29, 2005Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
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Patent number: 6926974Abstract: 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: GrantFiled: May 22, 2001Date of Patent: August 9, 2005Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
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Publication number: 20050157431Abstract: 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: ApplicationFiled: October 29, 2004Publication date: July 21, 2005Applicant: Hitachi Global Storage Technologies Netherlands, B.V.Inventors: Masahiko Hatatani, Chiseki Haginoya, Kenichi Meguro, Kazuhiro Nakamoto
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Publication number: 20040150912Abstract: 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: ApplicationFiled: August 20, 2003Publication date: August 5, 2004Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
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Publication number: 20040100737Abstract: 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: ApplicationFiled: June 4, 2003Publication date: May 27, 2004Applicant: Hitachi, Ltd.Inventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa