Patents by Inventor Koji Shimazawa

Koji Shimazawa 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).

  • Publication number: 20100103562
    Abstract: 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: Application
    Filed: October 27, 2008
    Publication date: April 29, 2010
    Applicant: TDK CORPORATION
    Inventors: Takahiko Machita, Daisuke Miyauchi, Yoshihiro Tsuchiya, Tsutomu Chou, Shinji Hara, Koji Shimazawa
  • Publication number: 20100097724
    Abstract: Provided is an HGA with a radiation structure that can effectively get away the heat generated from a light source. The HGA comprises a suspension and a head comprising a slider and a light source unit. The suspension comprises an opening, and the light source unit projects through the opening to the opposite side to the slider in relation to the suspension. Further, the first and second pads are provided on the upper and lower surfaces of the suspension, respectively, the end surface opposite to the source-installation surface of the light source is connected to the first pad by the first connection member, and an electrode of the head part is connected to the second pad by the second connection member. Thus, heat flow paths can be provided from the light source to the opposed-to-medium surface to allow effective radiation of the heat generated from the light source.
    Type: Application
    Filed: October 16, 2008
    Publication date: April 22, 2010
    Applicants: TDK Corporation, SAE Magnetics (H.K.) Ltd.
    Inventors: Koji SHIMAZAWA, Ryuta MURAKOSHI
  • Publication number: 20100097722
    Abstract: The semiconductor oxide layer that forms a part of the spacer layer in the inventive giant magnetoresistive device (CPP-GMR device) is composed of zinc oxide of wurtzite structure that is doped with a dopant given by at least one metal element selected from the group consisting of Zn, Ge, V, and Cr in a content of 0.05 to 0.90 at %: there is the advantage obtained that ever higher MR ratios are achievable while holding back an increase in the area resistivity AR.
    Type: Application
    Filed: October 21, 2008
    Publication date: April 22, 2010
    Applicant: TDK CORPORATION
    Inventors: Tsutomu Chou, Tomohito Mizuno, Koji Shimazawa, Yoshihiro Tsuchiya, Shinji Hara, Hironobu Matsuzawa
  • Publication number: 20100085846
    Abstract: Provided is a method for manufacturing a heat-assisted magnetic recording head, capable of joining a light source unit and a slider with a sufficiently high alignment accuracy. In the method, the unit including a light source is joined to the slider including a head part. First, at least one marker provided on the head-part end surface is set so that the distance from the waveguide incident center to the marker end is substantially equal to the distance from the light-emission center of the light source to the end surface of the light source. After that, the unit and slider are relatively moved while keeping the unit in surface contact with the slider, and the relative positions are set so that the end of the marker coincides with, or is at a distance within an acceptable range from, the edge of the surface of the light source.
    Type: Application
    Filed: October 6, 2008
    Publication date: April 8, 2010
    Applicant: TDK CORPORATION
    Inventors: Koji SHIMAZAWA, Yasuhiro ITO
  • Publication number: 20100079895
    Abstract: Provided is a plasmon antenna in which a near-field light having a sufficient intensity is generated only in a desired location. The plasmon antenna comprises an end surface on a side where a near-field light is generated; the end surface is flat and has a shape with at least three vertexes or rounded corners; and an end surface of the plasmon antenna which is opposite to the flat end surface and receives light, is inclined with respect to the flat end surface so as to become closer to the flat end surface toward one of the at least three vertexes or rounded corners. When the light-receiving end surface of the plasmon antenna is irradiated with the light, a near-field light having a sufficient intensity can be generated at only the vertex or rounded corner toward which the entire plasmon antenna becomes thinner.
    Type: Application
    Filed: September 26, 2008
    Publication date: April 1, 2010
    Applicant: TDK Corporation
    Inventors: Seiichi Takayama, Eiji Komura, Kosuke Tanaka, Daisuke Miyauchi, Koji Shimazawa
  • Publication number: 20100079917
    Abstract: 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: Application
    Filed: September 29, 2008
    Publication date: April 1, 2010
    Applicant: TDK CORPORATION
    Inventors: Daisuke Miyauchi, Yoshihiro Tsuchiya, Tsutomu Chou, Shinji Hara, Takahiko Machita, Koji Shimazawa
  • Publication number: 20100073802
    Abstract: A thermally assisted magnetic head according to the present invention includes: a medium-facing surface, a main magnetic pole provided on the medium-facing surface, and a plasmon antenna provided on the medium-facing surface in the vicinity of the main magnetic pole, wherein the plasmon antenna is shaped as a triangular flat plate having first, second and third corners, such that the distance from the first corner to the main magnetic pole is shorter than the distance from the second corner to the main magnetic pole and the distance from the third corner to the main magnetic pole, and the interior angle ? of the first corner, the interior angle ? of the second corner and the interior angle ? of the third corner satisfy relationships ?<?, ?<? and ???.
    Type: Application
    Filed: September 25, 2008
    Publication date: March 25, 2010
    Applicant: TDK CORPORATION
    Inventors: Eiji KOMURA, Seiichi TAKAYAMA, Satoshi TOMIKAWA, Kosuke TANAKA, Koji SHIMAZAWA
  • Publication number: 20100073817
    Abstract: A plasmon antenna of the present invention is used in a thermally assisted magnetic head that includes: a medium-facing surface set, parallel to an XY plane; a magnetic pole for writing, extending toward the medium-facing surface, and a plasmon antenna comprising a pair of small metal bodies irradiated with excitation light for near-field light generation propagating in a Z-axis direction. Respective corners of the small metal bodies are spaced apart opposite each other along a TE mode direction of the excitation light. A distance between the corners gives the shortest distance between the small metal bodies, and a distance from each corner to the leading end of the magnetic pole gives a shortest distance from the small metal bodies to the leading end.
    Type: Application
    Filed: September 25, 2008
    Publication date: March 25, 2010
    Applicant: TDK CORPORATION
    Inventors: Seiichi TAKAYAMA, Eiji KOMURA, Yasuhiro ITO, Kosuke TANAKA, Koji SHIMAZAWA
  • Publication number: 20100074062
    Abstract: Provided is a magnetic recording medium that generates near-field light within itself and enables favorable heat-assisted magnetic recording with this near-field light. The medium comprises: a magnetic recording layer; and an optically changeable layer formed on the opposite side to a substrate relative to the magnetic recording layer, the optically changeable layer being made transparent or a refractive index of the layer being changed when irradiated by light with an intensity not less than a predetermined intensity. By the irradiation, a minute opening or a refractive-index-changed area is formed within the irradiated portion on the optically changeable layer. The light irradiation onto the minute opening or the refractive-index-changed area enables near-field light to be generated, which heats a portion of the magnetic recording layer. Thus, the anisotropic field of the portion is lowered to a writable value, which enables heat-assisted magnetic recording by applying write field.
    Type: Application
    Filed: September 19, 2008
    Publication date: March 25, 2010
    Applicant: TDK Corporation
    Inventors: Akifumi Kamijima, Koji Shimazawa
  • Patent number: 7683610
    Abstract: A method for inspecting magnetic characteristics of a thin film magnetic head that is arranged in a row bar includes: a step of preparing a row bar having sliders including a thin film magnetic head formed therein and lapping guides having magnetoresistance effect; a step of preparing a magnetic field applying row bar having first and second magnetic field applying elements; a first positioning step in which said magnetic field applying row bar is arranged opposite to said row bar; a second positioning step in which a relative movement between said magnetic field applying row bar and said row bar is made so that at least one of said lapping guides exhibits a largest output voltage; and a measurement step in which a relationship between the intensity of the magnetic field and an output voltage of a magnetic field sensor is obtained.
    Type: Grant
    Filed: March 3, 2008
    Date of Patent: March 23, 2010
    Assignee: TDK Corporation
    Inventor: Koji Shimazawa
  • Publication number: 20100061200
    Abstract: Provided is a near-field light generating element capable of avoiding excessive temperature rise, which comprises a waveguide and a near-field light generating layer. The layer comprises: a propagation surface on which surface plasmon excited by the light propagates; and a near-field light generating end at which near-field light is generated. The end is one end of the propagation surface. And a portion of the side surface of the waveguide is opposed to a portion of the propagation surface of the near-field light generating layer with a predetermined spacing so that the light propagating through the waveguide is coupled with the near-field light generating layer in a surface plasmon mode. The near-field light generating layer is preferably tapered toward the near-field light generating end.
    Type: Application
    Filed: September 5, 2008
    Publication date: March 11, 2010
    Applicant: TDK CORPORATION
    Inventors: Koji SHIMAZAWA, Eiji KOMURA, Yasuhiro ITO, Seiichi TAKAYAMA, Satoshi TOMIKAWA, Daisuke MIYAUCHI, Kosuke TANAKA
  • Publication number: 20100053820
    Abstract: 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: Application
    Filed: September 2, 2008
    Publication date: March 4, 2010
    Applicant: TDK CORPORATION
    Inventors: Daisuke Miyauchi, Yoshihiro Tsuchiya, Tsutomu Chou, Shinji Hara, Takahiko Machita, Koji Shimazawa
  • Patent number: 7672085
    Abstract: The invention provides a giant magneto-resistive effect device (CPP-GMR device) having a CPP (current perpendicular to plane) structure comprising a spacer layer, and a fixed magnetized layer and a free layer stacked one upon another with said spacer layer interleaved between them, with a sense current applied in a stacking direction, wherein the spacer layer comprises a first and a second nonmagnetic metal layer, each formed of a nonmagnetic metal material, and a semiconductor oxide layer interleaved between the first and the second nonmagnetic metal layer, wherein the semiconductor oxide layer that forms a part of the spacer layer is made of indium oxide (In2O3), or the semiconductor oxide layer contains indium oxide (In2O3) as its main component, and an oxide containing a tetravalent cation of SnO2 is contained in the indium oxide that is the main component.
    Type: Grant
    Filed: January 24, 2007
    Date of Patent: March 2, 2010
    Assignee: TDK Corporation
    Inventors: Shinji Hara, Kei Hirata, Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno
  • Patent number: 7672092
    Abstract: A method for manufacturing a magnetic field detecting element has the steps of: forming stacked layers by sequentially depositing a pinned layer, a spacer layer, a spacer adjoining layer which is adjacent to the spacer layer, a metal layer, and a Heusler alloy layer in this order, such that the layers adjoin each other; and heat treating the stacked layers in order to form the free layer out of the spacer adjoining layer, the metal layer, and the Heusler alloy layer. The spacer adjoining layer is mainly formed of cobalt and iron, and has a body centered cubic structure, and the metal layer is formed of an element selected from the group consisting of silver, gold, copper, palladium, or platinum, or is formed of an alloy thereof.
    Type: Grant
    Filed: February 21, 2007
    Date of Patent: March 2, 2010
    Assignee: TDK Corporation
    Inventors: Yoshihiro Tsuchiya, Tomohito Mizuno, Kei Hirata, Keita Kawamori, Koji Shimazawa
  • Publication number: 20100046331
    Abstract: A planar plasmon antenna is formed on a YZ plane including a Z-axis, the Z-axis being a propagation direction of excitation light for near-field light generation. The longitudinal direction of the planar plasmon antenna is oblique relative to the Y-axis, and the angle of a corner of the planar plasmon antenna in the YZ plane is an acute angle. The corner, which forms an acute angle, generates intense near-field light in response to excitation light irradiation.
    Type: Application
    Filed: August 20, 2008
    Publication date: February 25, 2010
    Applicant: TDK CORPORATION
    Inventors: Seiichi TAKAYAMA, Koji SHIMAZAWA
  • Patent number: 7663845
    Abstract: A current-perpendicular-to-plane magneto-resistive element includes a magneto-resistive film and a pair of upper and lower magnetic shielding films holding the magneto-resistive film therebetween for current feeding. The lower magnetic shielding film has an at least two-layer structure including a crystalline material layer and an amorphous material layer disposed below the crystalline material layer.
    Type: Grant
    Filed: December 27, 2006
    Date of Patent: February 16, 2010
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Koji Shimazawa, Atsushi Yamaguchi, Kiyoshi Noguchi
  • Patent number: 7656621
    Abstract: A magneto-resistive element has: a first stacked film assembly having a pinned layer, a spacer layer, and a free layer; a first electrode layer which is arranged such that the first layer is in contact with the first electrode layer on the other side of the first layer, the first electrode layer being made of a ferromagnetic material; and a second electrode layer which is arranged on a side that is opposite to the first electrode layer with regard to the first stacked film assembly. The first and second electrode layers are adapted to apply a sense current to the first stacked film assembly and the first layer in a direction that is perpendicular to layer surfaces. The first layer is made of gold, silver, copper, ruthenium, rhodium, iridium, chromium or platinum, or an alloy thereof.
    Type: Grant
    Filed: October 17, 2006
    Date of Patent: February 2, 2010
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Daisuke Miyauchi, Tomohito Mizuno, Yoshihiro Tsuchiya
  • Publication number: 20100020431
    Abstract: In a heat-assisted magnetic recording, a thin-film magnetic head, which can form stable recording bits pattern having steep magnetization transition regions without using a near-field light generating element, is provided. The head is formed on an element forming surface of a substrate, and has a waveguide for leading a light for heat-assist to a magnetic medium and a write element formed on a trailing side of the waveguide and having a magnetic pole for applying a write field to the medium. Here, a write field profile, which is an intensity distribution of the write field from the pole along a track in a recoding layer of the medium, has a projecting region on a leading side. Further, an anisotropy field profile, which is a distribution of an anisotropy field when the anisotropy field is reduced by irradiating the light on a part of the recoding layer, traverses the projecting region.
    Type: Application
    Filed: July 22, 2008
    Publication date: January 28, 2010
    Applicant: TDK Corporation
    Inventors: Koji SHIMAZAWA, Daisuke MIYAUCHI, Katsuki KURIHARA
  • Publication number: 20090310244
    Abstract: Provided is a thin-film magnetic head that can stably generate electromagnetic field with a desired frequency, even under the existence of significantly strong write field with frequently reversed direction. The head comprises an electromagnetic-field generating element between the first and second magnetic poles. The electromagnetic-field generating element comprises a spin-wave excitation layer provided adjacent to the first magnetic pole and having a magnetization with its direction varied according to external magnetic fields, for generating an high frequency electromagnetic field by an excitation of spin wave. And a magnetization of the spin-wave excitation layer is biased in a direction substantially perpendicular to its layer surface by a portion of magnetic field generated from the first magnetic pole, and pin-wave excitation current flows in the electromagnetic-field generating element in a direction from the second pole to the first pole.
    Type: Application
    Filed: June 17, 2008
    Publication date: December 17, 2009
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Tsutomu Chou, Yoshihiro Tsuchiya
  • Publication number: 20090303640
    Abstract: 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: Application
    Filed: April 25, 2008
    Publication date: December 10, 2009
    Applicant: TDK CORPORATION
    Inventors: Tomohito Mizuno, Koji Shimazawa, Yoshihiro Tsuchiya, Daisuke Miyauchi, Takahiko Machita, Shinji Hara, Tsutomu Chou, Hironobu Matsuzawa, Toshiyuki Ayukawa, Tsuyoshi Ichiki