Patents by Inventor Takeo Kagami

Takeo Kagami 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: 20090038143
    Abstract: A method is provided for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.
    Type: Application
    Filed: September 24, 2008
    Publication date: February 12, 2009
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
  • Publication number: 20090040660
    Abstract: A thin-film magnetic head includes a lower magnetic shield layer, an MR multi-layered structure formed on the lower magnetic shield layer so that current flows in a direction perpendicular to surfaces of laminated layers, an upper magnetic shield layer formed on the MR multi-layered structure, and an additional lower magnetic shield layer directly laminated on the lower magnetic shield layer outside both side ends in a track-width direction of the MR multi-layered structure. The additional lower magnetic shield layer is directly contacted with both side surfaces in a track-width direction of the MR multi-layered structure. A top surface of the additional lower magnetic shield layer is positioned higher in height than a top surface of the lower magnetic shield layer in a region where the MR multi-layered structure is formed.
    Type: Application
    Filed: August 9, 2007
    Publication date: February 12, 2009
    Applicant: TDK CORPORATION
    Inventors: Takeo KAGAMI, Takayasu KANAYA
  • Patent number: 7489481
    Abstract: A magnetic head is provided for further improving a correlation between the dynamic characteristics and static characteristics. A lower magnetic shield layer, a magneto-resistive layer, and an upper magnetic shield layer are laminated on a base in this order. A lower lead layer and an upper lead layer apply a sense current to the magneto-resistive layer in a direction substantially perpendicular to the film plane thereof through the magnetic shield layers. The lower magnetic shield layer and upper magnetic shield layer have their shapes and sizes which substantially exactly overlap each other, when viewed in a laminating direction. The lower lead layer is electrically connected to the lower magnetic shield layer. At least a portion of the lower lead layer closer to the lower magnetic shield layer is made of a non-magnetic conductive material. The upper lead layer is electrically connected to the upper magnetic shield layer.
    Type: Grant
    Filed: February 28, 2005
    Date of Patent: February 10, 2009
    Assignee: TDK Corporation
    Inventors: Kentaro Nagai, Takeo Kagami, Noriaki Kasahara, Naoki Ohta, Satoshi Miura
  • Publication number: 20080291579
    Abstract: A noise-testing method for a thin-film magnetic head with an MR read head element and a heating unit capable of applying a heat and a stress to the MR read head element, includes a step of applying alternately and discontinuously with each other an electrical power having a first level and an electrical power having a second level higher than the first level to the heating unit, and a step of evaluating the thin-film magnetic head by measuring a noise output or noise outputs obtained from the MR read head element when the electrical power or the electrical powers are applied to the heating unit.
    Type: Application
    Filed: May 25, 2007
    Publication date: November 27, 2008
    Applicants: TDK CORPORATION, SAE MAGNETICS (H.K.) LTD.
    Inventors: Takumi Uesugi, Takeo Kagami, Tetsuro Sasaki, Kei Hirata, Masaru Hirose, Chi Man Lee, Kwok Piu Tso
  • Publication number: 20080291582
    Abstract: Provided is a thin film magnetic head capable of suppressing an occurrence of a track erase, decreasing an influence on a magnetoresistive element caused by a magnetic flux generated from a thin film coil, and further decreasing the parasitic capacity. The thin film magnetic head has, in order in a stacked direction, a first magnetic shield layer, a magnetoresistive element, a second magnetic shield layer, a third magnetic shield layer, a main magnetic pole layer and a return yoke layer. A width in a track width direction of at least one of the first and the second magnetic shield layers is smaller than widths in a track width direction of the third magnetic shield layer and the return yoke layer.
    Type: Application
    Filed: May 21, 2007
    Publication date: November 27, 2008
    Applicant: TDK CORPORATION
    Inventors: Kei Hirata, Norikazu Ota, Yuichi Watabe, Tetsuro Sasaki, Takeo Kagami, Tetsuya Roppongi, Kazuki Sato, Yuji Otsubo, Sohei Horiuchi, Yoshiaki Tanaka, Kenji Yokoyama, Noriaki Kasahara
  • Publication number: 20080253037
    Abstract: A thin-film magnetic head includes a lower magnetic shield layer, an MR multi-layered structure formed on the lower magnetic shield layer so that current flows in a direction perpendicular to surfaces of laminated layers, an insulation layer formed to surround the MR multi-layered structure, an additional metal layer laminated on at least the MR multi-layered structure, an upper electrode layer made of a soft magnetic material laminated on the additional metal layer and the insulation layer, and an upper magnetic shield layer laminated on the upper electrode layer. The additional metal layer has a multi-layered structure including a nonmagnetic metal layer and a soft magnetic layer laminated on the nonmagnetic metal layer, and has a length along a track-width direction of the MR multi-layered structure larger than a width of a magnetization-free layer in the MR effect multi-layered structure.
    Type: Application
    Filed: April 11, 2007
    Publication date: October 16, 2008
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Kazuki Sato, Kosuke Tanaka, Takayasu Kanaya, Naoki Ohta
  • Publication number: 20080253036
    Abstract: A thin-film magnetic head includes a lower magnetic shield layer, an MR multi-layered structure formed on the lower magnetic shield layer so that current flows in a direction perpendicular to surfaces of laminated layers, and an upper magnetic shield layer formed on the MR multi-layered structure. The lower magnetic shield layer consists of a first soft magnetic layer and a second soft magnetic layer laminated on and magnetically connected with the first soft magnetic layer. A part of an upper surface of the first soft magnetic layer outside both side ends in a track-width direction of the MR multi-layered structure is located lower in height than an upper surface within a region where the MR multi-layered structure is formed, of the lower magnetic shield layer. The second soft magnetic layer is formed outside both side ends in a track-width direction of the MR multi-layered structure.
    Type: Application
    Filed: April 16, 2007
    Publication date: October 16, 2008
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Takayasu Kanaya
  • Patent number: 7436633
    Abstract: A parasitic capacity C4 generated between a slider substrate and the first shield layer with the first insulating layer as a capacity layer is made substantially equal to a parasitic capacity C2 occurring between a lower magnetic layer and the second shield layer with the third insulating layer as a capacity layer. Preferably, a connection is made between the lower magnetic layer and the slider substrate by a resistance of preferably 100 (?) or lower. Thus, it is possible to provide a thin-film magnetic head that can hold back deterioration in a reproducing device and the occurrence of errors due to crosstalk between a recording device and the reproducing device and extraneous noises.
    Type: Grant
    Filed: August 17, 2005
    Date of Patent: October 14, 2008
    Assignee: TDK Corporation
    Inventors: Hiroshi Kiyono, Tetsuya Kuwashima, Takeo Kagami, Noriaki Kasahara, Naoki Ohta, Nozomu Hachisuka
  • Publication number: 20080222878
    Abstract: A method of manufacturing a magnetic head includes the steps of: fabricating a substructure in which pre-head portions are aligned in a plurality of rows by forming components of a plurality of magnetic heads on a single substrate; and fabricating the plurality of magnetic heads by separating the pre-head portions from one another through cutting the substructure. In the step of fabricating the substructure, the resistance of an MR film that will be formed into an MR element by undergoing lapping later is detected to determine the target position of the boundary between a track width defining portion and a wide portion of a pole layer based on the resistance thus obtained, and the pole layer is thereby formed. In the step of fabricating the magnetic heads, the surface formed by cutting the substructure is lapped such that the MR film is lapped and the resistance thereof thereby reaches a predetermined value.
    Type: Application
    Filed: March 16, 2007
    Publication date: September 18, 2008
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Tetsuro Sasaki, Yuichi Watabe, Takamitsu Sakamoto
  • Publication number: 20080222879
    Abstract: A method of manufacturing a magnetic head includes the steps of: fabricating a substructure in which pre-head portions are aligned in a plurality of rows by forming components of a plurality of magnetic heads on a single substrate; and fabricating the plurality of magnetic heads by separating the pre-head portions from one another through cutting the substructure. In the step of fabricating the substructure, the resistance of an MR film that will be formed into an MR element by undergoing lapping later is detected to determine the target position of the boundary between a track width defining portion and a wide portion of a pole layer based on the resistance detected, and the pole layer is thereby formed. In the step of fabricating the magnetic heads, the surface formed by cutting the substructure is lapped such that the MR film is lapped and the resistance thereof thereby reaches a predetermined value.
    Type: Application
    Filed: December 27, 2007
    Publication date: September 18, 2008
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Tetsuro Sasaki, Yuichi Watabe, Takamitsu Sakamoto
  • Publication number: 20080218912
    Abstract: An MR element includes: a free layer whose direction of magnetization changes in response to a signal magnetic field; a pinned layer whose direction of magnetization is fixed; and a spacer layer disposed between these layers. The spacer layer includes: a semiconductor layer made of an n-type semiconductor; and a Schottky barrier forming layer made of a metal material having a work function higher than that of the n-type semiconductor that the semiconductor layer is made of, the Schottky barrier forming layer being disposed in at least one of a position between the semiconductor layer and the free layer and a position between the semiconductor layer and the pinned layer, touching the semiconductor layer and forming a Schottky barrier at an interface between the semiconductor layer and itself The semiconductor layer is 1.1 to 1.7 nm in thickness, and the Schottky barrier forming layer is 0.1 to 0.3 nm in thickness.
    Type: Application
    Filed: March 9, 2007
    Publication date: September 11, 2008
    Applicant: TDK CORPORATION
    Inventors: Kei Hirata, Satoshi Miura, Takeo Kagami, Tetsuro Sasaki
  • Publication number: 20080218915
    Abstract: Provided is a TMR effect element having no special structures needing much man-hour cost for the formation, in which the high temperature noise and the low temperature noise are suppressed and a sufficiently high resistance-change ratio is provided. The TMR effect element comprises: a tunnel barrier layer formed by oxidizing a base film; and two ferromagnetic layers stacked so as to sandwich the tunnel barrier layer, the base film having a film thickness larger than a film thickness at which a resistance-change ratio of the TMR effect element indicates a maximum value. Here, in the case that the base film is an aluminum film, the film thickness of the aluminum film is preferably in the range of 0.50 nm to 1.5 nm.
    Type: Application
    Filed: March 5, 2007
    Publication date: September 11, 2008
    Applicant: TDK CORPORATION
    Inventors: Takumi Uesugi, Satoshi Miura, Tetsuro Sasaki, Takeo Kagami, Kei Hirata
  • Publication number: 20080204938
    Abstract: Provided is a thin-film magnetic head in which a noise due to the voltage potential difference between the read head element and the protective coat surface is suppressed. The thin-film magnetic head comprises: a read head element, one end surface of the read head element reaching an head end surface on the ABS side; a protective coat formed on the head end surface in such a way to cover at least the one end surface of the read head element; and at least one antistatic means for preventing the protective coat from being electrostatically charged, formed on/above the element formation surface, one end surface of the at least one antistatic means reaching the head end surface, the protective coat covering a portion, not the whole, of the one end surface of the at least one antistatic means on the head end surface.
    Type: Application
    Filed: February 26, 2007
    Publication date: August 28, 2008
    Applicant: TDK Corporation
    Inventors: Kei Hirata, Takeo Kagami, Takumi Uesugi, Tetsuro Sasaki
  • Patent number: 7398591
    Abstract: The present invention relates to a manufacturing method of a thin-film magnetic head whereby re-deposition and an overlapped part in a region of a magnetoresistive effect multi-layered structure opposite to an air bearing surface can be removed and also a width of a free layer can be narrowed.
    Type: Grant
    Filed: October 25, 2004
    Date of Patent: July 15, 2008
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Takayasu Kanaya, Noriaki Kasahara, Kazuki Sato
  • Publication number: 20080144226
    Abstract: A thin-film magnetic head includes a lower electrode layer, an MR multi-layered structure, through which a current passes in a direction perpendicular to a lamination plane, stacked on the lower electrode layer, soft magnetic layers for magnetic domain control formed on both sides in a track width direction of the MR multi-layered structure, an anti-ferromagnetic layer for magnetic domain control continuously stacked on the MR multi-layered structure and the soft magnetic layers for magnetic domain control, the anti-ferromagnetic layer mutually exchanged-coupled to the soft magnetic layers for magnetic domain control, and an upper electrode layer stacked on the anti-ferromagnetic layer for magnetic domain control.
    Type: Application
    Filed: December 13, 2006
    Publication date: June 19, 2008
    Applicant: TDK CORPORATION
    Inventor: Takeo Kagami
  • Patent number: 7372282
    Abstract: A method for testing a TMR element includes a step of measuring a plurality of resistances of the TMR element by applying a plurality of voltages with different voltage values each other to the TMR element, respectively, a step of calculating a ratio of change in resistance from the measured plurality of resistances of the TMR element, and a step of evaluating the TMR element using the calculated ratio of change in resistance.
    Type: Grant
    Filed: March 13, 2006
    Date of Patent: May 13, 2008
    Assignee: TDK Corporation
    Inventors: Nozomu Hachisuka, Hiroshi Kiyono, Takeo Kagami, Kenji Inage, Norio Takahashi
  • Patent number: 7352539
    Abstract: The method of making a thin-film magnetic head in accordance with the present invention forms a cover layer on an insulating layer about a magnetoresistive film so as to eliminate a protrusion riding on the magnetoresistive film. The protrusion can be eliminated by etching. The part of insulating layer clad with the cover layer is not etched. This can prevent short-circuit from occurring because of thinning the insulating layer.
    Type: Grant
    Filed: September 15, 2006
    Date of Patent: April 1, 2008
    Assignee: TDK Corporation
    Inventors: Kazuki Sato, Takeo Kagami
  • Publication number: 20080074800
    Abstract: A manufacturing method of a thin-film magnetic head with an MR read head element, includes an MR film deposition step of depositing on a lower magnetic shield layer an MR multi-layered film, a first patterning step of patterning the deposited MR multi-layered film for defining a track width using a first mask, a first lift-off step of depositing at least an insulation film and a magnetic domain control film under a state where the first mask used the first patterning step is remained and removing the first mask to form a magnetic domain control layer, a second patterning step of patterning the MR multi-layered films for defining a width in a height direction that is perpendicular to a track-width direction to form a MR multi-layered structure, and a upper shield layer deposition step of depositing an upper magnetic shield layer.
    Type: Application
    Filed: September 14, 2007
    Publication date: March 27, 2008
    Applicant: TDK CORPORATION
    Inventors: Takeo KAGAMI, Naoki OHTA, Kosuke TANAKA
  • Publication number: 20080043370
    Abstract: An MR element includes a free layer whose direction of magnetization changes in response to an external magnetic field. Two bias magnetic field applying layers are disposed adjacent to two side surfaces of the MR element. Each bias magnetic field applying layer includes a nonmagnetic intermediate layer, and a first magnetic layer and a second magnetic layer disposed to sandwich the intermediate layer. The first and second magnetic layers are antiferromagnetically exchange-coupled to each other through RKKY interaction.
    Type: Application
    Filed: July 13, 2007
    Publication date: February 21, 2008
    Applicant: TDK CORPORATION
    Inventors: Kei Hirata, Shinji Hara, Takayasu Kanaya, Takeo Kagami
  • Publication number: 20080030908
    Abstract: A magnetoresistive effect (MR) element, a thin-film magnetic head having the MR element, a method for manufacturing the MR element, and a method for manufacturing the thin-film magnetic head are disclosed. The MR element, which uses electric current in a direction perpendicular to layer planes, includes a lower electrode layer, a MR multilayered structure formed on the lower electrode layer, a magnetic domain controlling bias layer that is disposed on both sides of the MR multilayered structure along the track-width direction and is made of a material at least partially including an hcp structure, a metal layer made of a material having a bcc structure formed on the magnetic domain controlling bias layer and the MR multilayered structure to cover the magnetic domain controlling bias layer and the MR multilayered structure, and an upper electrode layer formed on the metal layer.
    Type: Application
    Filed: June 18, 2007
    Publication date: February 7, 2008
    Applicant: TDK Corporation
    Inventors: Takeo Kagami, Kosuke Tanaka, Shinji Hara, Takayasu Kanaya, Nobuyoshi Morizumi