Patents by Inventor Koichi Terunuma

Koichi Terunuma 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: 20030053265
    Abstract: A magnetoresistive effective film responds commensurate with an external magnetic field. Magnetic domain-controlling films apply a perpendicular biasing magnetic field to the magnetoresistive effective film. The forefronts of first electrode films constituting a pair of electrode films are overlaid on the magnetoresistive effective film, and the forefront surfaces of the first electrode films are risen at an inner angle of &thgr;1. Second electrode films are overlaid on the first electrode films, and the forefront surfaces of the second electrode films are risen at an inner angle of &thgr;2 smaller than the inner angle &thgr;1.
    Type: Application
    Filed: July 10, 2002
    Publication date: March 20, 2003
    Applicant: TDK CORPORATION
    Inventors: Koichi Terunuma, Koji Shimazawa, Akifumi Kamijima
  • Publication number: 20030043514
    Abstract: A read head comprises an MR element, two bias field applying layers, and two conductive layers. The two bias field applying layers are adjacent to both side portions of the MR element, and apply a bias magnetic field to the MR element along the longitudinal direction. The two conductive layers feed a sense current to the MR element, each of the conductive layers being disposed to be adjacent to one of surfaces of each of the bias field applying layers and to overlap one of surfaces of the MR element. The conductive layers are each made of a gold alloy having a resistivity of less than 22 &mgr;&OHgr;·cm and a hardness as high as or higher than the hardness of a material used for making the bias field applying layers.
    Type: Application
    Filed: July 12, 2002
    Publication date: March 6, 2003
    Applicant: TDK Corporation
    Inventors: Noriyuki Ito, Kosuke Tanaka, Koichi Terunuma
  • Publication number: 20020163767
    Abstract: A magnetic domain controlling film is provided on a soft magnetic film, and magnetizes the soft magnetic film in one direction. The magnetic domain controlling film has a large first thickness t1 enough to magnetize the soft magnetic film at both ends in the magnetization direction of the soft magnetic film, and has a small second thickness t2 enough for the magnetization of the soft magnetic film to be rotated at the central part in the magnetization direction of the soft magnetic film. The magnetic domain controlling film covers the soft magnetic film almost entirely.
    Type: Application
    Filed: May 15, 2002
    Publication date: November 7, 2002
    Applicant: TDK Corporation
    Inventor: Koichi Terunuma
  • Patent number: 6477018
    Abstract: A thin-film magnetic head includes a substrate with a surface, first and second shield layers formed above the substrate, and a MR sensor element formed between the first and second shield layers. The MR sensor element has a magnetic sensing region formed with a specific slant angle against the surface of the substrate.
    Type: Grant
    Filed: July 8, 1999
    Date of Patent: November 5, 2002
    Assignee: TDK Corporation
    Inventor: Koichi Terunuma
  • Publication number: 20020159206
    Abstract: A magnetoresisive device comprises: an MR element having two surfaces that face toward opposite directions and two side portions that face toward opposite directions; two bias field applying layers that are located adjacent to the side portions of the MR element and apply a longitudinal bias magnetic field to the MR element; and two electrode layers that are located adjacent to one of the surfaces of each of the bias field applying layers and feed a sense current to the MR element. The electrode layers overlap the one of the surfaces of the MR element. The magnetoresistive device further comprises two nonconductive layers that are located between the one of the surfaces of the MR element and the two electrode layers and located in two regions that include ends of the MR element near the side portions thereof, the two regions being parts of the region in which the electrode layers face toward the one of the surfaces of the MR element.
    Type: Application
    Filed: August 3, 2001
    Publication date: October 31, 2002
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Koichi Terunuma
  • Publication number: 20020157238
    Abstract: A magnetoresistive device comprises: an MR element; two bias field applying layers that apply a longitudinal bias magnetic field to the MR element; and two electrode layers that are located adjacent to one of the surfaces of each of the bias field applying layers and overlap one of the surfaces of the MR element. The MR element incorporates a protection layer located on a soft magnetic layer. In the method of manufacturing the magnetoresistive device, a coating layer that will be removed in a later step is formed on the protection layer in advance. Before forming the electrode layers, the coating layer and an oxide layer that is formed through natural-oxidizing part of the top surface of the coating layer are removed through etching. After the electrode layers are formed, the portion of the protection layer located in the region between the two electrode layers is oxidized, and a high resistance layer is thereby formed.
    Type: Application
    Filed: August 3, 2001
    Publication date: October 31, 2002
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Noriyuki Ito, Koichi Terunuma
  • Patent number: 6466415
    Abstract: The invention provides a thin film magnetic head including a first pole portion having depressed portion that is formed therein. The depressed portion descends, backward within the first pole portion, at a first inclination angle &thgr;1 from a first inclination starting point P1. Then, an insulating film is filled up in the depressed portion so that it can be located up to the upper side of the surface of the first pole and have an inclined surface in the side of a medium opposing surface. Additionally, a first magnetic film of a second pole portion can have a larger saturated magnetic flux density than a second magnetic film of the second pole portion, and can include an inclined portion with a second inclination angle &thgr;2 from a second inclination starting point P2.
    Type: Grant
    Filed: June 28, 2000
    Date of Patent: October 15, 2002
    Assignee: TDK Corporation
    Inventors: Koichi Terunuma, Tetsuya Mino, Katsuya Kanakubo, Noriyuki Ito
  • Publication number: 20020145834
    Abstract: Each of the first and second shield gap films has a highly insulative film made of aluminum oxide. The highly insulative film has the insulating properties improved by heating. The insulating properties may be improved by heating after deposition or by depositing while heating. This heating allows the highly insulative film to have a reduced pinhole density and an increased dielectric breakdown field. Therefore, the insulating properties can be ensured even if a shield gap length is reduced, and thus it is possible to adapt to an increase in a recording density of a recording medium. The highly insulative film may have the insulating properties improved by exposing the film surface to an oxygen-plasma-containing atmosphere or oxygen-ion-containing atmosphere after deposition.
    Type: Application
    Filed: October 4, 1999
    Publication date: October 10, 2002
    Inventors: TORU INOUE, KOICHI TERUNUMA
  • Patent number: 6462917
    Abstract: A magnetoresistive sensor according to the present invention has a spin-valve film structure which includes an underfilm, a first ferromagnetic film, a conductive film, a second ferromagnetic film, an antiferromagnetic film and a protective film. One surface of the first ferromagnetic film is adjacent to the one surface of the underfilm, and the one surface of the conductive film is adjacent to the other surface of the first ferromagnetic film. One surface of the second ferromagnetic film is adjacent to the other surface of the conductive film. One surface of the antiferromagnetic film adjacent to the other surface of the second ferromagnetic film, and thus, the antiferromagnetic film is bonded to the second ferromagnetic film with exchange interaction. One surface of the protective film is adjacent to the other surface of the antiferromagnetic film. The underfilm has a face centered cubic crystal structure, and is oriented in the (111) plane direction.
    Type: Grant
    Filed: January 31, 2001
    Date of Patent: October 8, 2002
    Assignee: TDK Corporation
    Inventors: Koichi Terunuma, Tetsuro Sasaki, Kosuke Tanaka, Takumi Uesugi
  • Publication number: 20020126423
    Abstract: Provided are a thin film magnetic head and a method of manufacturing the same, which is capable of high density recording and obtaining stable output. The thin film magnetic head comprises an MR film sandwiched in between first and second shield layers. The first shield layer includes an inner layer, a magnetization stabilizing layer, an underlayer, and an outer layer laminated in order from the MR film. The second shield layer includes an inner layer, a magnetization stabilizing layer, an isolating layer, and an outer layer laminated in order from the MR film. The magnetization stabilizing layers are formed of antiferromagnetic material, so as to control the direction of magnetization of the inner layers.
    Type: Application
    Filed: November 26, 2001
    Publication date: September 12, 2002
    Applicant: TDK CORPORATION
    Inventors: Koichi Terunuma, Ken-ichi Takano, Noriyuki Ito
  • Patent number: 6444406
    Abstract: A method for forming a photoresist pattern, includes a step of forming a photoresist pattern having a certain width, and a step of performing thereafter ion milling with respect to side walls of the formed photoresist pattern by using an ion beam with a large incident angle so as to reduce the width of the formed photoresist pattern.
    Type: Grant
    Filed: July 6, 2001
    Date of Patent: September 3, 2002
    Assignee: TDK Corporation
    Inventors: Noriyuki Ito, Koichi Terunuma, Satoshi Tsukiyama
  • Publication number: 20020097531
    Abstract: A read head comprises: an MR element that detects a magnetic field; a pair of electrode layers for feeding a sense current to the MR element; and a bottom shield layer and a top shield layer that sandwich and shield the MR element and the electrode layers; a bottom insulating layer disposed between the MR element/the electrode layers and the bottom shield layer; a top insulating layer disposed between the MR element/the electrode layers and the top shield layer; a bottom semiconductor layer that is made up of a single layer and disposed between the electrode layers and the bottom shield layer, for connecting the electrode layers and the bottom shield layer; and a top semiconductor layer that is made up of a single layer and disposed between the electrode layers and the top shield layer, for connecting the electrode layers and the top shield layer.
    Type: Application
    Filed: November 15, 2001
    Publication date: July 25, 2002
    Applicant: TDK CORPORATION
    Inventors: Tohru Inoue, Shigeki Tanemura, Koichi Terunuma
  • Patent number: 6414825
    Abstract: An object of the invention is to improve the thermal conductivity and the hardness of a first shield gap film and a second shield gap film. Another object is to improve the thermal conductivity while decreasing the stress. The first shield gap film and the second shield gap film are formed of an insulating film which includes at least one of BN, SiN or CN as the main component, a little Ar and oxygen. Higher thermal conductivity can be obtained by using the insulating film which includes at least one of BN, SiN, or CN so that the heat generated in an MR element can be effectively dissipated. In addition, including Ar improves the hardness so that excessive polishing can be suppressed at the time of forming the air bearing surface. Moreover, including oxygen decreases the stress and exfoliation of the first and the second shield gap films can be avoided.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: July 2, 2002
    Assignee: TDK Corporation
    Inventors: Toru Inoue, Koichi Terunuma
  • Publication number: 20020075609
    Abstract: Provided are a thin film magnetic head and a method of manufacturing the same, which can prevent an output decrease without impairment of productivity and other characteristics, while adapting to an increase in a recording density. In the thin film magnetic head, an MR film is sandwiched in between first and second gap films having electrical insulating properties, which are sandwiched in between first and second shield layers. The first shield layer has an inner layer and an outer layer laminated in order from the MR film, and the second shield layer has an inner layer and an outer layer laminated in order from the MR film. The respective inner layers of the first and second shield layers have hardness higher than that of the respective outer layers thereof so as to prevent the first and second shield layers from deforming.
    Type: Application
    Filed: October 26, 2001
    Publication date: June 20, 2002
    Applicant: TDK CORPORATION
    Inventor: Koichi Terunuma
  • Patent number: 6404603
    Abstract: An object of the invention is to improve thermal conductivity of a first and a second shield gap films and to suppress a rise in temperature in an MR element. A first shield gap film and a second shield gap film are formed of an insulating film which includes AlN as a main component and the (002) plane of AlN is oriented to the vertical direction to the surface of the insulating film. As a result, higher thermal conductivity can be attained compared to the case where a plurality of crystal surfaces of AlN are oriented to the vertical direction to the surface of the insulating film, and the heat generated in the MR element can be effectively dissipated. The insulating film may include a small amount of Ar. In such a case, the hardness is increased preventing the first and second shield gap films from being excessively polished when forming an air bearing surface. The insulating film may also include oxygen.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: June 11, 2002
    Assignee: TDK Corporation
    Inventors: Toru Inoue, Koichi Terunuma
  • Publication number: 20020055264
    Abstract: A method for forming a photoresist pattern, includes a step of forming a photoresist pattern having a certain width, and a step of performing thereafter ion milling with respect to side walls of the formed photoresist pattern by using an ion beam with a large incident angle so as to reduce the width of the formed photoresist pattern.
    Type: Application
    Filed: July 6, 2001
    Publication date: May 9, 2002
    Inventors: Noriyuki Ito, Koichi Terunuma, Satoshi Tsukiyama
  • Patent number: 6381093
    Abstract: The present invention relates to a thin film magnetic head which eliminates the problems of degradation in the recording magnetic field pitch and recording bleed occurring due to leaked magnetic field by preventing magnetic saturation from occurring at pole tips. A write element is provided with a first pole portion, a second pole portion and a gap film. The gap film is provided between the first pole portion and the second pole portion. The second pole portion includes a third magnetic film and a fourth magnetic film. The third magnetic film is adjacent to the gap film and the fourth magnetic film is adjacent to the third magnetic film. The third magnetic film has a width W20 at a position receding from its surface facing opposite the medium by a receding quantity &Dgr;L, which is larger than the width W21 at the surface facing opposite the medium.
    Type: Grant
    Filed: September 29, 1998
    Date of Patent: April 30, 2002
    Assignee: TDK Corporation
    Inventors: Makoto Yoshida, Noboru Yamanaka, Koichi Terunuma, Yasufumi Uno
  • Publication number: 20020044398
    Abstract: A MR sensor includes at least one pinned layer, at least one nonmagnetic layer, and a free layer layered with the at least one pinned layer via the at least one nonmagnetic layer. A magnetization direction of the at least one pinned layer is fixed, and a magnetization direction of the free layer is variable depending upon a magnetic field applied to the free layer. A nonmagnetic metal is diffused in at least part of the free layer.
    Type: Application
    Filed: May 31, 2001
    Publication date: April 18, 2002
    Inventors: Tetsuro Sasaki, Koichi Terunuma, Kosuke Tanaka
  • Patent number: 6364964
    Abstract: The SVMR element has a non-magnetic metallic thin-film layer, first and second ferromagnetic thin-film layers (free and pinned layers) formed to sandwich the non-magnetic metallic thin-film layer and an anti-ferromagnetic thin-film layer formed in contact with a surface of the second ferromagnetic thin-film layer. This surface is opposite to the non-magnetic metallic thin-film layer. The first ferromagnetic thin-film layer has a two-layers structure of a NiFe layer and a CoFe layer. The manufacturing method includes a step of depositing the first ferromagnetic thin-film layer, the non-magnetic metallic thin-film layer, the second ferromagnetic thin-film layer and the anti-ferromagnetic thin-film layer, and a step of annealing, thereafter, the deposited layers so that change in magnetostriction depending upon variation of a thickness of the NiFe layer becomes small.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: April 2, 2002
    Assignee: TDK Corporation
    Inventors: Tetsuro Sasaki, Noriyuki Ito, Koichi Terunuma
  • Publication number: 20020036497
    Abstract: A magnetoresisive device comprises an MR element, bias field applying layers located adjacent to the side portions of the MR element, and two electrode layers that feed a sense current to the MR element. The electrode layers overlap one of the surfaces of the MR element. The total overlap amount of the two electrode layers is smaller than 0.3 &mgr;m. The MR element is a spin-valve GMR element. The MR element incorporates a base layer, a free layer, a spacer layer, a pinned layer, an antiferromagnetic layer, and a cap layer that are stacked in this order. The pinned layer includes a nonmagnetic spacer layer, and two ferromagnetic layers that sandwich this spacer layer.
    Type: Application
    Filed: July 25, 2001
    Publication date: March 28, 2002
    Applicant: TDK CORPORATION
    Inventors: Kenji Inage, Yoshihiro Kudo, Ken-ichi Takano, Koichi Terunuma, Yuzuru Iwai