Patents by Inventor Takahiko Machita
Takahiko Machita 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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Magnetoresistive element including a pair of ferromagnetic layers coupled to a pair of shield layers
Publication number: 20100103562Abstract: A magnetoresistive element includes a pair of shield portions, and an MR stack and a bias magnetic field applying layer that are disposed between the pair of shield portions. The shield portions respectively include single magnetic domain portions. The MR stack includes a pair of ferromagnetic layers magnetically coupled to the pair of single magnetic domain portions, and a spacer layer disposed between the pair of ferromagnetic layers. The MR stack has a front end face, a rear end face and two side surfaces. The magnetoresistive element further includes two flux guide layers disposed between the pair of single magnetic domain portions and respectively adjacent to the two side surfaces of the MR stack. Each of the two flux guide layers has a front end face and a rear end face. The bias magnetic field applying layer has a front end face that faces the rear end face of the MR stack and the respective rear end faces of the two flux guide layers.Type: ApplicationFiled: October 27, 2008Publication date: April 29, 2010Applicant: TDK CORPORATIONInventors: Takahiko Machita, Daisuke Miyauchi, Yoshihiro Tsuchiya, Tsutomu Chou, Shinji Hara, Koji Shimazawa -
Magnetoresistive element including a pair of ferromagnetic layers coupled to a pair of shield layers
Publication number: 20100103563Abstract: A magnetoresistive element includes first and second shield portions and an MR stack. Each of the first and second shield portions includes a shield bias magnetic field applying layer, and a closed-magnetic-path-forming portion that forms a closed magnetic path in conjunction of the shield bias magnetic field applying layer. The closed-magnetic-path-forming portion includes a single magnetic domain portion. The MR stack is sandwiched between the respective single magnetic domain portions of the first and second shield portions. The closed-magnetic-path-forming portion includes a magnetic-path-expanding portion that forms a magnetic path, the magnetic path being a portion of the closed magnetic path and located between the shield bias magnetic field applying layer and the single magnetic domain portion. The magnetic-path-expanding portion has two end portions located at both ends of the magnetic path, and a middle portion located between the two end portions.Type: ApplicationFiled: October 29, 2008Publication date: April 29, 2010Applicant: TDK CORPORATIONInventors: Takahiko Machita, Daisuke Miyauchi, Tsutomu Chou, Toshiyuki Ayukawa -
Publication number: 20100079917Abstract: A first shield portion located below an MR stack includes a first main shield layer, a first antiferromagnetic layer, and a first magnetization controlling layer including a first ferromagnetic layer exchange-coupled to the first antiferromagnetic layer. A second shield portion located on the MR stack includes a second main shield layer, a second antiferromagnetic layer, and a second magnetization controlling layer including a second ferromagnetic layer exchange-coupled to the second antiferromagnetic layer. The MR stack includes two free layers magnetically coupled to the two magnetization controlling layers. Only one of the two magnetization controlling layers includes a third ferromagnetic layer that is antiferromagnetically exchange-coupled to the first or second ferromagnetic layer through a nonmagnetic middle layer. The first shield portion includes an underlayer disposed on the first main shield layer, and the first antiferromagnetic layer is disposed on the underlayer.Type: ApplicationFiled: September 29, 2008Publication date: April 1, 2010Applicant: TDK CORPORATIONInventors: Daisuke Miyauchi, Yoshihiro Tsuchiya, Tsutomu Chou, Shinji Hara, Takahiko Machita, Koji Shimazawa
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Publication number: 20100067148Abstract: A thin film magnetic head comprises an MR laminated body that has first and second magnetic layers, a nonmagnetic middle layer, and the first and second magnetic layers and the nonmagnetic middle layer are laminated to make contact with each other in respective order. First and second antiferromagnetic layers are provided with the first and second magnetic layers respectively. The first antiferromagnetic layer and/or the second antiferromagnetic layer contains a void part or a thin portion at least in a portion of the projection area toward the orthogonal direction to the film surface of the MR laminated body.Type: ApplicationFiled: September 16, 2008Publication date: March 18, 2010Applicant: TDK CORPORATIONInventors: Yoshihiro Tsuchiya, Tsutomu Chou, Shinji Hara, Daisuke Miyauchi, Takahiko Machita
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Magnetoresistive element including a pair of ferromagnetic layers coupled to a pair of shield layers
Publication number: 20100053820Abstract: A magnetoresistive element includes first and second shield layers, an MR stack disposed therebetween, a first hard magnetic layer for setting the magnetization direction of the first shield layer, and a second hard magnetic layer for setting the magnetization direction of the second shield layer. The MR stack includes a first ferromagnetic layer magnetically coupled to the first shield layer, a second ferromagnetic layer magnetically coupled to the second shield layer, and a spacer layer between the first and second ferromagnetic layers. The first and second ferromagnetic layers have magnetizations that are in antiparallel directions when any external magnetic field other than a magnetic field resulting from the first and second hard magnetic layers is not applied to the two ferromagnetic layers, and that change their directions in response to an external magnetic field other than the magnetic field resulting from the first and second hard magnetic layers.Type: ApplicationFiled: September 2, 2008Publication date: March 4, 2010Applicant: TDK CORPORATIONInventors: Daisuke Miyauchi, Yoshihiro Tsuchiya, Tsutomu Chou, Shinji Hara, Takahiko Machita, Koji Shimazawa -
Publication number: 20100039734Abstract: A thin film magnetic head includes a magneto-resistance (MR) laminated body, a lower shield layer and an upper shield layer that face the first MR magnetic layer. The lower and upper shield layers respectively have first and second exchange coupling magnetic field application layers and first and second antiferromagnetic layers. An exchange coupling intensity relating to an antiferromagnetic coupling between the second exchange coupling magnetic field application layer and the second antiferromagnetic layer is greater in the peripheral area of a projection area than that of the projection area of the upper shield layer side end surface of the MR laminated body to the film surface's orthogonal direction.Type: ApplicationFiled: August 12, 2008Publication date: February 18, 2010Applicant: TDK CORPORATIONInventors: Shinji Hara, Yoshihiro Tsuchiya, Tsutomu Chou, Daisuke Miyauchi, Takahiko Machita
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Publication number: 20100027168Abstract: A thin film magnetic head comprise an MR laminated body composed of a first and second MR magnetic layers, first and second shield layers, and a bias magnetic field application layer provided on an opposite side of an air bearing surface (ABS) of the MR laminated body in order to apply a bias magnetic field orthogonal relative to the ABS. The first shield layer comprises a first exchange coupling magnetic field application layer, a first antimagnetic layer, a second exchange coupling magnetic field application layer, and a second antimagnetic layer. The first antimagnetic layer is provided in contact with the first exchange coupling magnetic field application layer on the rear face of the first exchange coupling magnetic field application layer and which is antimagnetically coupled with the first exchange coupling magnetic field application layer. The second shield layer has the same configuration as that of the first shield layer.Type: ApplicationFiled: July 29, 2008Publication date: February 4, 2010Applicant: TDK CORPORATIONInventors: Tsutomu Chou, Yoshihiro Tsuchiya, Shinji Hara, Daisuke Miyauchi, Takahiko Machita
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Publication number: 20090303640Abstract: A magneto resistance effect element includes a first magnetic layer, a second magnetic layer and a spacer layer interposed between the first and second magnetic layers. The magneto resistance effect element is configured to allow sense current to flow in a direction that is perpendicular to film planes of the first magnetic layer, the second magnetic layer and the spacer layer so that a relative angle between a magnetization direction of the first magnetic layer and a magnetization direction of the second magnetic layer varies depending on an external magnetic field. The present invention aims at providing a magneto resistance effect element which ensures high resistance to sense current, while limiting the influence of the current limiting layer on the magnetic layer, and which thereby achieves a high magneto resistance ratio.Type: ApplicationFiled: April 25, 2008Publication date: December 10, 2009Applicant: TDK CORPORATIONInventors: Tomohito Mizuno, Koji Shimazawa, Yoshihiro Tsuchiya, Daisuke Miyauchi, Takahiko Machita, Shinji Hara, Tsutomu Chou, Hironobu Matsuzawa, Toshiyuki Ayukawa, Tsuyoshi Ichiki
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Publication number: 20090290264Abstract: The invention provides a magnetoresistive device of the CPP (current perpendicular to plane) structure, comprising a magnetoresistive unit, and a first, substantially soft magnetic shield layer positioned below and a second, substantially soft magnetic shield layer positioned above, which are located and formed such that the magnetoresistive effect is sandwiched between them from above and below, with a sense current applied in the stacking direction. The magnetoresistive unit comprises a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed such that said nonmagnetic intermediate layer is sandwiched between them. At least one of the first shield layer positioned below and the second shield layer positioned above is configured in a framework form having a planar shape (X-Y plane) defined by the width and length directions of the device.Type: ApplicationFiled: May 23, 2008Publication date: November 26, 2009Applicant: TDK CORPORATIONInventors: Toshiyuki Ayukawa, Takahiko Machita, Daisuke Miyauchi, Tsutomu Chou, Koji Shimazawa, Shinji Hara, Tomohito Mizuno, Yoshihiro Tsuchiya
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Patent number: 7615996Abstract: An examination method is structured, with respect to a magnetization direction of an orthogonalizing bias function part formed on a posterior part of an magnetoresistance (MR) effect element, of changing the magnetization direction of the orthogonalizing bias function part between a first magnetization forming mode, wherein the magnetization direction is from the anterior side of the element to the posterior side thereof, and a second magnetization forming mode, wherein the magnetization direction is from the posterior side of the element to the anterior side thereof, measuring the output waveform of the element in response to an external magnetic field for each magnetization forming mode and checking the state of the output waveforms of both modes in order to examine whether or not the magnetization directions of the first magnetic layer and the second magnetic layer, both of which functions as free layers, are antiparallel to each other in the track width direction before the orthogonalizing bias function pType: GrantFiled: January 21, 2009Date of Patent: November 10, 2009Assignee: TDK CorporationInventors: Takahiko Machita, Kiyoshi Noguchi, Daisuke Miyauchi
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Publication number: 20090273864Abstract: A magnetoresistive element includes a first and a second shield, and an MR stack disposed between the shields. The MR stack includes a first and a second ferromagnetic layer, and a nonmagnetic spacer layer disposed between the ferromagnetic layers. The first and second ferromagnetic layers have magnetizations that are in directions antiparallel to each other when no external magnetic field is applied to the layers, and that change directions in response to an external magnetic field. An insulating layer is formed to touch a rear end face of the MR stack and the first shield, and a bias magnetic field applying layer is formed above the insulating layer with a buffer layer disposed in between. The bias magnetic field applying layer includes a hard magnetic layer and a high saturation magnetization layer. The high saturation magnetization layer is located between the rear end face and the hard magnetic layer, but not located between the first shield and the hard magnetic layer.Type: ApplicationFiled: December 27, 2007Publication date: November 5, 2009Applicant: TDK CORPORATIONInventors: Takahiko Machita, Kei Hirata, Koji Shimazawa, Daisuke Miyauchi
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Patent number: 7583478Abstract: A thin-film magnetic head comprises: a magnetoresistive element: first and second read shield layers disposed to sandwich the magnetoresistive element; and bias field applying layers for applying a bias magnetic field to the magnetoresistive element. Each of the first and second read shield layers has: a first end face located in a medium facing surface; a second end face opposite to the first end face; a first width changing portion that continuously decreases in width as the distance from the first end face decreases; and a second width changing portion that continuously decreases in width as the distance from the second end face decreases.Type: GrantFiled: July 7, 2006Date of Patent: September 1, 2009Assignee: TDK CorporationInventors: Takahiko Machita, Kei Hirata, Koji Shimazawa
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Publication number: 20090213502Abstract: A magneto-resistance effect element comprises: a magneto-resistance effect stack including an upper magnetic layer and a lower magnetic layer whose magnetization directions change in accordance with an external magnetic field, a non-magnetic intermediate layer sandwiched between the upper and lower magnetic layers; an upper shield electrode layer and a lower shield electrode layer which are provided to sandwich the magneto-resistance effect stack therebetween in the direction of stacking the magneto-resistance effect stack, wherein the upper shield electrode layer and the lower shield electrode layer supply sense current in the direction of stacking, and magnetically shield the magneto-resistance effect stack; a first bias magnetic layer which is provided on a surface of the magneto-resistance effect stack opposite to an air bearing surface, and wherein the first bias magnetic layer is magnetized in a direction perpendicular to said air bearing surface; and a pair of second bias magnetic layers provided on reType: ApplicationFiled: February 25, 2008Publication date: August 27, 2009Inventors: Daisuke MIYAUCHI, Koji SHIMAZAWA, Tsutomu CHOU, Takahiko MACHITA, I
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Publication number: 20090207534Abstract: A magneto-resistance effect element comprises; a magneto-resistance effect stack including an upper magnetic layer and a lower magnetic layer in which respective magnetization directions change in accordance with an external magnetic field, a non-magnetic intermediate layer sandwiched between the upper and lower magnetic layers, an upper gap adjustment layer and a lower gap adjustment layer provided at respective ends in the direction of stacking the magneto-resistance effect stack, an upper exchange coupling transmission layer configured to generate exchange coupling between the upper magnetic layer and the upper gap adjustment layer, and a lower exchange coupling transmission layer configured to generate exchange coupling between the lower magnetic layer and the lower gap adjustment layer; an upper shield electrode layer and a lower shield electrode layer which are provided to sandwich the magneto-resistance effect stack therebetween in the direction of stacking the magneto-resistance effect stack, whereinType: ApplicationFiled: February 19, 2008Publication date: August 20, 2009Applicant: TDK CorporationInventors: Daisuke MIYAUCHI, Koji SHIMAZAWA, Tsutomu CHOU, Takahiko MACHITA
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Publication number: 20090190272Abstract: The invention provides a magnetoresistive device with the CPP (current perpendicular to plane) structure, comprising a magnetoresistive unit, and a first shield layer and a second shield layer located and formed such that the magnetoresistive unit is sandwiched between them, with a sense current applied in a stacking direction, wherein said magnetoresistive unit comprises a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed such that said nonmagnetic intermediate layer is interposed between them, wherein said first shield layer, and said second shield layer is controlled by magnetization direction control means in terms of magnetization direction, and said first ferromagnetic layer, and said second ferromagnetic layer receives action such that there is an antiparallel magnetization state created, in which mutual magnetizations are in opposite directions, under the influences of magnetic actions of said first shield layer and said second shield lType: ApplicationFiled: January 24, 2008Publication date: July 30, 2009Applicant: TDK CorporationInventors: Takahiko Machita, Koji Shimazawa, Daisuke Miyauchi, Tsutomu Chou
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Publication number: 20090190268Abstract: A magnetoresistive device of a CPP (current perpendicular to plane) structure includes a magnetoresistive unit sandwiched between a first substantially soft magnetic shield layer from below, and a second substantially soft magnetic shield layer from above, with a sense current applied in a stacking direction. The magnetoresistive unit includes a non-magnetic intermediate layer sandwiched between a first ferromagnetic layer, and a second ferromagnetic layer. At least one of the first and second shield layers is configured in a window frame of a planar shape, including a front frame-constituting portion and a back frame-constituting portion partially comprising a combination of a nonmagnetic gap layer with a bias magnetic field-applying layer. The combination of the nonmagnetic gap layer with the bias magnetic field-applying layer forms a closed magnetic path with magnetic flux going all the way around the window framework, turning the magnetization of the front frame-constituting portion into a single domain.Type: ApplicationFiled: January 24, 2008Publication date: July 30, 2009Applicant: TDK CorporationInventors: Takahiko Machita, Koji Shimazawa, Daisuke Miyauchi, Tsutomu Chou
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Publication number: 20090190270Abstract: The invention provides a magnetoresistive device with the CPP (current perpendicular to plane) structure, comprising a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed with said nonmagnetic intermediate layer interposed between them, with a sense current applied in the stacking direction, wherein each of said first and second ferromagnetic layers comprises a sensor area joining to the nonmagnetic intermediate layer near a medium opposite plane and a magnetization direction control area that extends further rearward (toward the depth side) from the position of the rear end of said nonmagnetic intermediate layer; a magnetization direction control multilayer arrangement is interposed at an area where the magnetization direction control area for said first ferromagnetic layer is opposite to the magnetization direction control area for said second ferromagnetic layer in such a way that the magnetizations of the said first and second ferromagnetic lType: ApplicationFiled: January 30, 2008Publication date: July 30, 2009Applicant: TDK CorporationInventors: Tsutomu Chou, Yoshihiro Tsuchiya, Daisuke Miyauchi, Takahiko Machita, Shinji Hara, Tomohito Mizuno, Hironobu Matsuzawa, Toshiyuki Ayukawa, Koji Shimazawa, Kiyoshi Noguchi
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Patent number: 7558027Abstract: A magnetic field sensor comprises: a magnetic field detecting element that detects magnitude of an external magnetic field based on electric resistance of the magnetic field detecting element to sense current, the electric resistance being varied in accordance with the external magnetic field; an upper shield layer that is formed to cover the magnetic field detecting element; and a protective layer that is formed above the upper shield layer with respect to a direction of stacking. The upper shield layer includes a first portion at least part of which covers a top surface of the magnetic field detecting element, and a second portion that covers the first portion, and, the first portion has a larger absolute value of magnetostriction than the second portion.Type: GrantFiled: April 26, 2006Date of Patent: July 7, 2009Assignee: TDK CorporationInventors: Kei Hirata, Takahiko Machita, Koji Shimazawa, Kiyoshi Noguchi
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Patent number: 7551407Abstract: A read head comprises: a bottom shield layer; a top shield layer; an MR element disposed between the bottom shield layer and the top shield layer; a bottom shield gap film disposed between the bottom shield layer and the MR element; and a top shield gap film disposed between the top shield layer and the MR element. The MR element has a first end closer to the air bearing surface and a second end opposite to the first end. An adjacent layer made of a metal material is adjacent to the second end with an insulating film disposed in between. The material making up the adjacent layer has a linear thermal expansion coefficient whose absolute value is 6×10?6/° C. or smaller at a temperature of 30° C., and preferably 1×10?6/° C. or smaller.Type: GrantFiled: March 7, 2005Date of Patent: June 23, 2009Assignee: TDK CorporationInventors: Takahiko Machita, Koji Shimazawa
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Patent number: 7542233Abstract: A perpendicular magnetic recording element includes a recording magnetic pole film and a write shield film. The recording magnetic pole film has a yoke portion and a main magnetic pole for perpendicular recording. The main magnetic pole projects from a front end of the yoke portion to have an end on a medium-facing surface. The write shield film faces the recording magnetic pole film and has a height equal to or smaller than that of the recording magnetic pole film, as measured rearward from the medium-facing surface.Type: GrantFiled: January 24, 2006Date of Patent: June 2, 2009Assignee: TDK CorporationInventors: Kei Hirata, Takahiko Machita, Kiyoshi Noguchi