Patents by Inventor Katsumi Hoshino
Katsumi Hoshino 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: 7876536Abstract: Embodiments of the present invention provides sufficiently high exchange coupling with a magnetic layer and improve the yield and reliability of a magnetoresistive head. By using a tilted growth crystalline structured antiferromagnetic film manufactured by an oblique incident deposition method, a high exchange coupling field with a ferromagnetic film can be obtained. As a result, excellent reliability and high output can be obtained in a magnetoresistive head utilizing features in accordance with embodiments of the present invention.Type: GrantFiled: April 4, 2007Date of Patent: January 25, 2011Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Katsumi Hoshino, Hiroyuki Hoshiya, Kenichi Meguro, Yo Sato
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Patent number: 7859797Abstract: Embodiments in accordance with the present invention provide a Current Perpendicular to the Plane—Giant Magnetoresistive (CPP-GMR) head exhibiting a high magnetoresistance (MR) ratio with a low area-resistance product. A lower shield is made up of a first shield layer/a crystalline reset layer/a second shield layer, and an amorphous material is used in at least a part of the crystalline reset layer, thereby controlling crystallinity of the second lower shield/the CPP-GMR head.Type: GrantFiled: January 18, 2007Date of Patent: December 28, 2010Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Katsumi Hoshino, Hiroyuki Hoshiya, Yasuyuki Okada
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Publication number: 20100188771Abstract: A magnetoresistive magnetic head according to one embodiment uses a current-perpendicular-to-plane magnetoresistive element having a laminate of a free layer, an intermediate layer, and a pinned layer, the pinned layer being substantially fixed to a magnetic field to be detected, wherein either the pinned layer or the free layer includes a Heusler alloy layer represented by a composition of X-Y-Z, wherein X is between about 45 at. % and about 55 at. % and is Co or Fe, Y accounts for between about 20 at. % and about 30 at. % and is one or more elements selected from V, Cr, Mn, and Fe, and Z is between about 20 at. % and about 35 at.Type: ApplicationFiled: December 11, 2009Publication date: July 29, 2010Inventors: Susumu Okamura, Yo Sato, Katsumi Hoshino, Hiroyuki Hoshiya, Kenichi Meguro, Keizo Kato
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Publication number: 20100157465Abstract: One general embodiment of the present invention is a magnetic read head including a magnetoresistive sensor where sense current flows in a stacking direction of the magnetoresistive sensor, i.e., perpendicular to the plane of the layers of the head. The magnetoresistive sensor comprises a free layer having a magnetization direction that is affected by external magnetic fields and includes a Heusler alloy layer and a Co-based amorphous metal layer, a fixed layer which is stacked with the free layer and has a fixed magnetization direction, and a non-magnetic intermediate layer between the free layer and the fixed layer.Type: ApplicationFiled: December 18, 2009Publication date: June 24, 2010Inventors: Koji Sakamoto, Koichi Nishioka, Katsuya Mitsuoka, Katsumi Hoshino, Yo Sato
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Publication number: 20100142101Abstract: According to one embodiment, a differential magnetoresistive effect element comprises a first magnetoresistive effect element having a first pinning layer, a first intermediate layer, and a first free layer. The differential magnetoresistive effect element also comprises a second magnetoresistive effect element stacked via a spacer layer above the first magnetoresistive effect element, the second magnetoresistive effect element having a second pinning layer, a second intermediate layer, and a second free layer. The first magnetoresistive effect element and the second magnetoresistive effect element show in-opposite-phase resistance change in response to a magnetic field in the same direction, and tp2>tp1 is satisfied when a thickness of the first pinning layer is tp1, and a thickness of the second pinning layer is tp2. In another embodiment, the first and second magnetoresistive effect elements may be CPP-GMR elements.Type: ApplicationFiled: December 1, 2009Publication date: June 10, 2010Inventors: Yo Sato, Katsumi Hoshino, Masato Shiimoto, Takeshi Nakagawa, Hiroyuki Hoshiya
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Patent number: 7733614Abstract: 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: GrantFiled: January 24, 2007Date of Patent: June 8, 2010Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Kenichi Meguro, Hiroyuki Katada, Katsumi Hoshino, Hiroyuki Hoshiya
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Patent number: 7697245Abstract: 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: GrantFiled: October 19, 2006Date of Patent: April 13, 2010Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Hiroyuki Hoshiya, Katsumi Hoshino, Kenichi Meguro, Yo Sato, Hiroyuki Katada
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Publication number: 20090262465Abstract: Embodiments of the present invention provide a magnetic head having a read head of stable reading operation and with less magnetic fluctuation noise. According to one embodiment, a free layer has a structure comprising two ferromagnetic layers (a first free layer and a second free layer) that are coupled anti-ferromagnetically by way of a non-magnetic intermediate layer, in which the magnetization amount of the first free layer is set to larger than the magnetization amount of the second free layer. Further, the magnetic domains in the first free layer and the second free layer are stabilized simultaneously by increasing the distance between the second free layer and the magnetic domain control film to be more than the distance between the first free layer and the magnetic domain control film, thereby adjusting the magnetization amount of the magnetic domain control film.Type: ApplicationFiled: April 17, 2009Publication date: October 22, 2009Inventors: Masahiko Hatatani, Katsuro Watanabe, Nubuo Yoshida, Katsumi Hoshino
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Publication number: 20090168266Abstract: Embodiments of the present invention provide a practical magneto-resistive effect element for CPP-GMR, which exhibits appropriate resistance-area-product and high magnetoresistance change ratio, and meets the demand for a narrow read gap. Certain embodiments of a magneto-resistive effect element in accordance with the present invention include a pinned ferromagnetic layer containing a first ferromagnetic film having a magnetization direction fixed in one direction, a free ferromagnetic layer containing a second ferromagnetic film having a magnetization direction varying in response to an external magnetic field, an intermediate layer provided between the pinned ferromagnetic layer and the free ferromagnetic layer, and a current confinement layer for confining a current. At least one of the pinned ferromagnetic layer or the free ferromagnetic layer includes a highly spin polarized layer.Type: ApplicationFiled: November 21, 2008Publication date: July 2, 2009Inventors: Yo Sato, Katsumi Hoshino, Hiroyuki Hoshiya
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Publication number: 20090034135Abstract: 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: ApplicationFiled: July 17, 2008Publication date: February 5, 2009Applicant: Hitachi Global Storage TechnologiesInventors: Hiroyuki Hoshiya, Kenichi Meguro, Katsumi Hoshino, Yo Sato, Hiroyuki Katada, Kazuhiro Nakamoto
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Patent number: 7443636Abstract: Embodiments of the invention implement a construction capable of reconciling high read output with high stability by improving the structures of magnetic films. In one embodiment, an inclined crystal grain structure is applied to a soft magnetic free layer, ferromagnetic pinned layer and so forth, thereby enhancing electron scatter performance of thin magnetic films.Type: GrantFiled: November 10, 2005Date of Patent: October 28, 2008Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Katsumi Hoshino, Hiroyuki Hoshiya, Kenichi Meguro, Yasuyuki Okada
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Patent number: 7440240Abstract: Embodiments of the invention provide a spin-valve type magnetic head that satisfies the requirements of both high read output and stability with narrow tracks. In one embodiment, a domain control film is formed on a magnetoresistive layered film in the same track width. A double closed flux path structure that uses three magnetic layers is employed with magnetic coupled structure in both ends of the track. The three magnetic layers are a soft magnetic free layer, a domain-stabilization ferromagnetic layer, and a soft magnetic anti-parallel layer.Type: GrantFiled: April 8, 2005Date of Patent: October 21, 2008Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Hiroyuki Hoshiya, Katsumi Hoshino, Masahiko Hatatani, Kenichi Meguro
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Patent number: 7440241Abstract: 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: GrantFiled: October 3, 2005Date of Patent: October 21, 2008Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Katsumi Hoshino, Hiroyuki Hoshiya, Hiroyuki Katada, Kenichi Meguro
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Publication number: 20080144231Abstract: Embodiments of the present invention provide a magnetic head incorporating a CPP-GMR device having a high output at a suitable resistance. According to one embodiment, in a Current Perpendicular to Plane-Giant Magneto Resistive (CPP-GMR) head comprising a pinned layer, a free layer, and a current screen layer for confining current therein, a planarization treatment is applied to the surface of the current screen layer, thereby allowing the current screen layer to have a fluctuation in film thickness thereof. As a result of the fluctuation being provided in the film thickness of the current screen layer, parts of the current screen layer, smaller in the film thickness, will be selectively turned into metal areas low in resistance, and as the metal areas low in resistance serve as current paths, effects of confining current can be adjusted by controlling the fluctuation in the film thickness.Type: ApplicationFiled: November 29, 2007Publication date: June 19, 2008Applicant: Hitachi Global Storage Technologies Netherlands B. V.Inventors: Yo Sato, Katsumi Hoshino, Hiroyuki Hoshiya
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Publication number: 20070297097Abstract: Embodiments in accordance with the present invention provide a magnetic head of the CPP structure for perpendicular magnetic recording, that is excellent in read performance, and stable in write/read performances by enhancing the external field durability, and further, suppresses deterioration in read sensor property, due to thermal factors. At least either shield layer of a lower magnetic shield layer, and an upper magnetic shield layer, closer to a perpendicular magnetic write head, is made up so as to have a multi-layered structure comprising low thermal expansion nonmagnetic layers, and magnetic layers. Material having a coefficient of thermal expansion smaller than that of a magnetoresistive film is selected as a material for the low thermal expansion nonmagnetic layers of the shield layer.Type: ApplicationFiled: May 29, 2007Publication date: December 27, 2007Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Katsuro Watanabe, Katsumi Hoshino, Masafumi Mochizuki
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Publication number: 20070274009Abstract: Embodiments of the present invention provides sufficiently high exchange coupling with a magnetic layer and improve the yield and reliability of a magnetoresistive head. By using a tilted growth crystalline structured antiferromagnetic film manufactured by an oblique incident deposition method, a high exchange coupling field with a ferromagnetic film can be obtained. As a result, excellent reliability and high output can be obtained in a magnetoresistive head utilizing features in accordance with embodiments of the present invention.Type: ApplicationFiled: April 4, 2007Publication date: November 29, 2007Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Katsumi Hoshino, Hiroyuki Hoshiya, Kenichi Meguro, Yo Sato
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Publication number: 20070188934Abstract: 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: ApplicationFiled: January 24, 2007Publication date: August 16, 2007Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Kenichi Meguro, Hiroyuki Katada, Katsumi Hoshino, Hiroyuki Hoshiya
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Publication number: 20070188944Abstract: Embodiments in accordance with the present invention provide a Current Perpendicular to the Plane-Giant Magnetoresistive (CPP-GMR) head exhibiting a high magnetoresistance (MR) ratio with a low area-resistance product. A lower shield is made up of a first shield layer/a crystalline reset layer/a second shield layer, and an amorphous material is used in at least a part of the crystalline reset layer, thereby controlling crystallinity of the second lower shield/the CPP-GMR head.Type: ApplicationFiled: January 18, 2007Publication date: August 16, 2007Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Katsumi Hoshino, Hiroyuki Hoshiya, Yasuyuki Okada
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Publication number: 20070091511Abstract: 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: ApplicationFiled: October 19, 2006Publication date: April 26, 2007Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Hiroyuki Hoshiya, Katsumi Hoshino, Kenichi Meguro, Yo Sato, Hiroyuki Katada
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Patent number: 7061727Abstract: A magnetoresistive includes a magnetoresistive layer which converts magnetic signals to electric signals and a pair of electrodes for allowing an electrically sensing current to flow across the magnetoresistive layer is made between an upper shield and an under shield with upper gap layer and under gap layer intervening between the magnetoresistive layer and the shields. By using a multi-layered varistor film or films of a material such as ZnO, SiC, SrTiO, Si etc. in combination with an insulating material SiO2, A1203, etc. to connect the magnetoresistive element to the shields and interconnect both electrodes, a magnetoresistive head which withstands breakdown even if the insulating gap layers are made thinner is provided.Type: GrantFiled: August 29, 2001Date of Patent: June 13, 2006Assignee: Hitachi, Ltd.Inventors: Katsumi Hoshino, Hiroyuki Hoshiya