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).

  • Patent number: 7805828
    Abstract: A method of manufacturing a thin-film magnetic head including forming the first shield layer; forming the magnetoresistive device, carried out after forming the first shield layer, a heat treatment providing exchange coupling between the ferromagnetic layer and the antiferromagnetic layer so as to magnetize the ferromagnetic layer in a predetermined direction; forming the domain control layer so as to hold the magnetoresistive device in a track width direction; magnetizing the domain control layer in a direction yielding a magnetic field in the same direction as with a magnetic field received by the ferromagnetic layer upon exchange-coupling with the antiferromagnetic layer, forming the second shield layer, carried out after magnetizing the domain control layer, and remagnetizing the domain control layer in a direction yielding the longitudinal bias magnetic field, carried out after forming the second shield layer.
    Type: Grant
    Filed: May 23, 2007
    Date of Patent: October 5, 2010
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Yoshihiro Tsuchiya
  • Patent number: 7804655
    Abstract: A thermally assisted magnetic head has a slider having a medium-facing surface, and a light source unit having a light source support substrate, and a light source disposed on the light source support substrate. The slider has a slider substrate and a magnetic head portion disposed on a side of the medium-facing surface in the slider substrate; the magnetic head portion includes a magnetic recording element for generating a magnetic field, and a waveguide for receiving light through an end face opposite to the medium-facing surface, and guiding the light to the medium-facing surface; the light source support substrate is fixed to a surface opposite to the medium-facing surface in the slider substrate so that light emitted from the light source can enter the end face of the waveguide.
    Type: Grant
    Filed: August 16, 2007
    Date of Patent: September 28, 2010
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Kosuke Tanaka, Takaaki Domon
  • Patent number: 7804667
    Abstract: An MR element incorporates a nonmagnetic conductive layer, and a pinned layer and a free layer that are disposed to sandwich the nonmagnetic conductive layer. Each of the pinned layer and the free layer includes a Heusler alloy layer. The Heusler alloy layer contains a Heusler alloy in which atoms of a magnetic metallic element are placed at body-centered positions of unit cells, and an additive element that is a nonmagnetic metallic element that does not constitute the Heusler alloy. At least one of the pinned layer and the free layer includes a region in which the concentration of the additive element increases as the distance from the nonmagnetic conductive layer decreases, the region being adjacent to the nonmagnetic conductive layer.
    Type: Grant
    Filed: March 20, 2007
    Date of Patent: September 28, 2010
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Yoshihiro Tsuchiya, Tomohito Mizuno, Koji Shimazawa
  • Publication number: 20100238580
    Abstract: A thermally-assisted magnetic recording head is provided, in which a light source with a sufficient power is disposed in the element-integration surface to improve mass-productivity. The head comprises, in an element-integration surface of a substrate: a light source; a waveguide for propagating light from the light source; and a magnetic pole for generating write field. Further, the edge along optical axis of the light source is set to be parallel with or inclined from the edge on the opposed-to-medium surface side of the element-integration surface. In the head, since the light source is disposed in the element-integration surface, the construction of the optical system can be completed in the stage of a wafer process. This construction can be relatively facilitated and simplified; thus, mass-productivity in the head manufacturing can be improved. Further, a light source with a sufficient power (cavity length) can be disposed in the element-integration surface.
    Type: Application
    Filed: March 19, 2009
    Publication date: September 23, 2010
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Eiji Komura
  • Publication number: 20100232074
    Abstract: A magnetoresistive effect element is structured in the manner that the antiferromagnetic layer interposed between the upper and lower shields is eliminated and the antiferromagnetic layer is positioned in a so-called shield layer. Therefore, it is realized to solve a pin reversal problem and to allow narrower tracks and narrower read gaps.
    Type: Application
    Filed: March 13, 2009
    Publication date: September 16, 2010
    Applicant: TDK CORPORATION
    Inventors: Takahiko Machita, Tomohito Mizuno, Koji Shimazawa, Tsutomu Chou, Daisuke Miyauchi, Yoshihiro Tsuchiya, Shinji Hara, Toshiyuki Ayukawa
  • Patent number: 7782575
    Abstract: An MR element includes: a free layer having a direction of magnetization that changes in response to a signal magnetic field; a pinned layer having a fixed direction of magnetization; and a spacer layer disposed between these layers. The spacer layer includes a first nonmagnetic metal layer and a second nonmagnetic metal layer each made of a nonmagnetic metal material, and a semiconductor layer that is made of a material containing an oxide semiconductor and that is disposed between the first and second nonmagnetic metal layers. The MR element has a resistance-area product within a range of 0.1 to 0.3?ยท?m2, and the spacer layer has a conductivity within a range of 133 to 432 S/cm.
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: August 24, 2010
    Assignee: TDK Corporation
    Inventors: Yoshihiro Tsuchiya, Kei Hirata, Tomohito Mizuno, Koji Shimazawa
  • Publication number: 20100202256
    Abstract: A near-field light generating device includes: a base having a top surface; a waveguide that allows laser light to propagate therethrough and is disposed above the top surface of the base; and a surface plasmon generating element that is disposed above the top surface of the base so as to adjoin the waveguide in a direction parallel to the top surface of the base. The waveguide has a side surface that faces the surface plasmon generating element. The surface plasmon generating element includes: a coupling part that is opposed to a part of the side surface of the waveguide with spacing therebetween and causes excitation of a surface plasmon by coupling with evanescent light occurring from the part of the side surface; and a near-field light generating part that generates near-field light based on the surface plasmon excited at the coupling part.
    Type: Application
    Filed: February 9, 2009
    Publication date: August 12, 2010
    Applicant: TDK CORPORATION
    Inventors: Yasuhiro Ito, Seiichi Takayama, Eiji Komura, Koji Shimazawa, Satoshi Tomikawa, Shuichi Okawa
  • Publication number: 20100202081
    Abstract: A thermally assisted magnetic head includes a slider having a medium-facing surface and a surface-emitting semiconductor laser. The slider has a slider substrate on which part of the medium-facing surface is formed, and a magnetic head portion, on which another part of the medium-facing surface is formed, and which has a first surface in contact with a head stacking surface of the slider substrate, a second surface opposite the first surface, and a third surface opposite the medium-facing surface. The magnetic head portion comprises a main magnetic pole, an optical waveguide core having a first light exit surface at the medium-facing surface and a second light exit surface at the third surface, a first diffraction grating, provided in the optical waveguide core or further towards the second surface than the optical waveguide core, and a light reflective section provided further toward the first surface than the optical waveguide core.
    Type: Application
    Filed: February 12, 2009
    Publication date: August 12, 2010
    Applicant: TDK CORPORATION
    Inventors: Koji SHIMAZAWA, Yasuhiro ITO, Seiichi TAKAYAMA
  • Patent number: 7773342
    Abstract: A thin-film magnetic head for a heat-assisted magnetic recording which can perform a reliable writing immediately only on a desired track by applying a near-field light to a desired position and range is provided. The head comprises: an electromagnetic coil element for writing data signals, having a pole end reaching a head end surface; and a near-field-light-generating portion for heating a portion of a magnetic recording medium during write operation by generating a near-field light, having a generation end reaching the head end surface and provided adjacent to the pole end and in the leading side of the pole end, and a shape of the generation end on the head end surface being a trapezoid with a shorter edge on the trailing side, or being a triangle with an apex on the trailing side and with a bottom on the leading side.
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: August 10, 2010
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Katsumichi Tagami
  • Publication number: 20100195238
    Abstract: A thermally assisted magnetic head includes: a slider having a medium-facing surface; and a surface-emitting semiconductor laser. The slider has: a slider substrate, on which part of the medium-facing surface is formed; and a magnetic head portion, on which another part of the medium-facing surface is formed, and which has a first surface in contact with a head stacking surface of the slider substrate and a second surface opposite the first surface. The magnetic head portion has: a main magnetic pole that generates a write magnetic field from an end face on the side of the medium-facing surface; an optical waveguide core extending along the first surface and having a light exit surface at the medium-facing surface; and a diffraction grating, which is provided in the optical waveguide core or further towards the second surface than the optical waveguide core, and the refractive index of which varies periodically along the direction in which the optical waveguide core extends.
    Type: Application
    Filed: January 30, 2009
    Publication date: August 5, 2010
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Eiji Komura, Seiichi Takayama
  • Publication number: 20100195239
    Abstract: The present thermally assisted magnetic head has: a plasmon antenna; an optical wave guide having the plasmon antenna installed at the tip thereof; a diffraction grating which is disposed in or on the optical wave guide; and a laser element which is disposed at a position to irradiate laser beams onto the diffraction grating, and is composed of a photonic crystal surface emitting semiconductor layer. A laser light intensity distribution on the diffraction grating has at least two intensity peaks in the width direction of the optical wave guide. The two-dimensional form of the laser light intensity distribution on the diffraction grating is a ring or two ellipses.
    Type: Application
    Filed: February 3, 2009
    Publication date: August 5, 2010
    Applicant: TDK CORPORATION
    Inventors: Seiichi TAKAYAMA, Koji SHIMAZAWA
  • Patent number: 7764470
    Abstract: A magneto-resistance effect element used for a thin film magnetic head is configured by a buffer layer, an anti-ferromagnetic layer, a pinned layer, a spacer layer, a free layer, and a cap layer, which are laminated in this order, and a sense current flows through the element in a direction orthogonal to the layer surface, via a lower shield layer and a upper shield layer. The pinned layer comprises an outer layer in which a magnetization direction is fixed, a non-magnetic intermediate layer, and an inner layer which is a ferromagnetic layer. The spacer layer comprises a first and second non-magnetic metal layer, and a semiconductor layer. The first and second non-magnetic metal layer and comprise CuPt films having a thickness of more than 0 nm but no more than 2.0 nm, and the Pt content ranges from a minimum of 5 to a maximum of 25 at %.
    Type: Grant
    Filed: March 6, 2007
    Date of Patent: July 27, 2010
    Assignee: TDK Corporation
    Inventors: Tomohito Mizuno, Kei Hirata, Yoshihiro Tsuchiya, Koji Shimazawa
  • Publication number: 20100182003
    Abstract: A magnetic film sensor comprises a magnetic film for generating a magnetostriction, and a magnetostrictive structure for generating a magnetostriction in the magnetic film. The magnetostrictive structure is constructed so as to generate a magnetostriction by curving the magnetic film, for example. The magnetostrictive structure is obtained, for example, by providing a depressed insulating layer having a surface formed with a depression and forming the magnetic film across the depression.
    Type: Application
    Filed: March 17, 2010
    Publication date: July 22, 2010
    Applicants: HEADWAY TECHNOLOGIES, INC., SAE MAGNETICS (H.K.) LTD.
    Inventors: Yoshitaka Sasaki, Koji Shimazawa, Tatsushi Shimizu
  • Publication number: 20100172220
    Abstract: Provided is a near-field light generating element in which as much amount as possible of waveguide light can be coupled with a plasmon antenna. The element comprises a light waveguide and a plasmon antenna comprising a surface or edge for propagating surface plasmon excited by waveguide light, extending to a near-field light generating end. A groove is formed in a waveguide side surface. And at least a portion of the surface or edge is embedded in the groove or located directly above the groove, being opposed to a wall or bottom surface of the groove with a predetermined distance, so as for waveguide light to be coupled with the plasmon antenna in surface plasmon mode. This configuration enables the surface or edge to be located at the position in which the surface or edge can be coupled with more amount of light, thereby to improve the light use efficiency.
    Type: Application
    Filed: January 7, 2009
    Publication date: July 8, 2010
    Applicant: TDK Corporation
    Inventors: Eiji Komura, Koji Shimazawa
  • Patent number: 7750627
    Abstract: A magnetic film sensor comprises a magnetic film for generating a magnetostriction, and a magnetostrictive structure for generating a magnetostriction in the magnetic film. The magnetostrictive structure is constructed so as to generate a magnetostriction by curving the magnetic film, for example. The magnetostrictive structure is obtained, for example, by providing a depressed insulating layer having a surface formed with a depression and forming the magnetic film across the depression.
    Type: Grant
    Filed: October 24, 2006
    Date of Patent: July 6, 2010
    Assignees: Headway Technologies, Inc., SAE Magnetics (H.K.) Ltd.
    Inventors: Yoshitaka Sasaki, Koji Shimazawa, Tatsushi Shimizu
  • Patent number: 7739787
    Abstract: In an MR element, each of a pinned layer and a free layer includes a Heusler alloy layer. The Heusler alloy layer has two surfaces that are quadrilateral in shape and face toward opposite directions. The Heusler alloy layer includes one crystal grain that touches four sides of one of the two surfaces. In a method of manufacturing the MR element, a layered film to be the MR element is formed and patterned, and then heat treatment is performed on the layered film patterned, so that crystal grains included in a film to be the Heusler alloy layer in the layered film grow and one crystal grain that touches four sides of one of the surfaces of the film to be the Heusler alloy layer is thereby formed.
    Type: Grant
    Filed: March 8, 2007
    Date of Patent: June 22, 2010
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Yoshihiro Tsuchiya, Tomohito Mizuno, Daisuke Miyauchi, Shinji Hara, Takahiko Machita
  • Publication number: 20100149930
    Abstract: Provided is a near-field light generating element in which reduced is the propagation loss of excited surface plasmon that propagates to the near-field light generating end. The element comprises: a waveguide through which light for exciting surface plasmon propagates; and a plasmon antenna comprising a near-field light generating end and a propagation surface or edge. The propagation surface or edge extends to the near-field light generating end, and causes surface plasmon excited by the light to propagate thereon. Further, a portion of the side surface on the near-field light generating end side is opposed to the propagation surface or edge with a predetermined distance so as for the light to be coupled with the plasmon antenna in a surface plasmon mode. In this configuration, surface plasmon can propagates without significantly changing its wavenumber, which leads to a less propagation loss, and to an improved light use efficiency.
    Type: Application
    Filed: December 16, 2008
    Publication date: June 17, 2010
    Applicant: TDK Corporation
    Inventors: Eiji Komura, Koji Shimazawa, Daisuke Miyauchi
  • Publication number: 20100118431
    Abstract: The thermally assisted magnetic head according to the present invention comprises 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. The shape of the plasmon antenna, as viewed from a direction perpendicular to the medium-facing surface, is a triangle having first, second and third corners, the plasmon antenna being shaped as a flat plate the thickness direction of which is perpendicular to the medium-facing surface. 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. The second corner and the third corner are rounded.
    Type: Application
    Filed: November 7, 2008
    Publication date: May 13, 2010
    Applicant: TDK CORPORATION
    Inventors: Satoshi TOMIKAWA, Seiichi TAKAYAMA, Koji SHIMAZAWA
  • Patent number: 7710677
    Abstract: A thermally assisted magnetic head has a medium-facing surface facing a medium, and comprises: a waveguide an end face of which is exposed in the medium-facing surface; an electroconductive near-field light generator plate disposed on a medium-facing surface of the waveguide so that a principal face thereof faces the medium; and an electroconductive near-field light scatter plate disposed on the medium-facing surface of the thermally assisted magnetic head so that a principal face thereof faces the medium; when viewed from a direction perpendicular to the medium-facing surface, the near-field light generator plate has a cusp portion at an end; when viewed from the direction perpendicular to the medium-facing surface, the near-field light scatter plate is arranged along the other end opposite to the cusp portion of the near-field light generator plate; when viewed from the direction perpendicular to the medium-facing surface, a width of the near-field light scatter plate in a first direction perpendicular to a
    Type: Grant
    Filed: December 17, 2007
    Date of Patent: May 4, 2010
    Assignee: TDK Corporation
    Inventors: Kosuke Tanaka, Koji Shimazawa
  • Publication number: 20100103553
    Abstract: Provided is a surface plasmon antenna that can be set so that the emitting position on the end surface of the plasmon antenna where near-field light is emitted is located sufficiently close to the end of a magnetic pole. The surface plasmon antenna comprises an edge having a portion for coupling with a light in a surface plasmon mode. The edge is provided for propagating surface plasmon excited by the light and extends from the portion to a near-field light generating end surface that emits near-field light. The edge for propagating surface plasmon is a very narrow propagation region. Therefore, the near-field light generating end surface, which appears as a polished surface processed through polishing in the manufacturing of the plasmon antenna, can be made a shape with a very small size, and further can be set so that surface plasmon propagates to reach the end surface reliably.
    Type: Application
    Filed: October 29, 2008
    Publication date: April 29, 2010
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Eiji Komura, Yasuhiro Ito, Seiichi Takayama, Satoshi Tomikawa, Daisuke Miyauchi, Kosuke Tanaka