Patents by Inventor Eiji Umetsu

Eiji Umetsu 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: 7443635
    Abstract: A multilayer film is placed on a subatrate. The multilayer film includes an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic material layer, and a free magnetic layer. The multilayer film has recessed sections arranged in both side regions thereof, the recessed sections being formed by partly removing the multilayer film in a vacuum. The bottoms of the recessed sections are located between the upper face and lower face of the antiferromagnetic layer. Amorphous barrier layers with a thickness of ? are placed on the bottoms of the recessed sections, the amorphous barrier layers being formed in the same vacuum as that for forming the recessed sections sequentially to the step of forming the recessed sections.
    Type: Grant
    Filed: October 4, 2005
    Date of Patent: October 28, 2008
    Assignee: Alps Electric Co., Ltd.
    Inventors: Kenichi Tanaka, Eiji Umetsu, Masahiro Oshima, Naoya Hasegawa
  • Patent number: 7433161
    Abstract: A nonmagnetic material-noncontact layer forming a fixed magnetic layer is formed using CoFe, a nonmagnetic material-contact layer is formed using Co, and an NOL (Nano-Oxide Layer) is provided between the nonmagnetic material-noncontact layer and the nonmagnetic material-contact layer. In addition, the average film thickness of the nonmagnetic material-contact layer is set in the range of 16 to 19 ?. Accordingly, compared to a three-layered structure composed of CoFe, an NOL, and CoFe or a three-layered structure composed of Co, an NOL, and Co, which has been conventionally used, the rate (?R/R) of change in resistance and the unidirectional exchange bias magnetic field (Hex*) can both be improved.
    Type: Grant
    Filed: January 12, 2005
    Date of Patent: October 7, 2008
    Assignee: Alps Electric Co., Ltd.
    Inventors: Kazuaki Ikarashi, Naoya Hasegawa, Fumihito Koike, Eiji Umetsu
  • Publication number: 20080174921
    Abstract: A second fixed magnetic layer is formed of a CoFeB layer of CoFeB and an interface layer of CoFe or Co provided in that order from the bottom. An insulating barrier layer composed of Al—O is formed on the second fixed magnetic layer. When a lamination structure composed of CoFeB/CoFe/Al—O is formed as described above, a low RA and a high rate of change in resistance (?R/R) can be simultaneously obtained. In addition, variations in RA and rate of change in resistance (?R/R) can be suppressed as compared to that in the past.
    Type: Application
    Filed: September 21, 2007
    Publication date: July 24, 2008
    Inventors: Kazuaki Ikarashi, Eiji Umetsu, Kenichi Tanaka, Kota Asatsuma
  • Patent number: 7397639
    Abstract: A magnetic detecting element, which can suppress change in output asymmetry even if the magnetization direction of a pinned magnetic layer is changed 180°, is provided. The magnetic-film-thickness of a second free magnetic layer is increased so as to be greater than that of a first free magnetic layer and offset the torque applied to the second free magnetic layer with that applied to the first free magnetic layer when the sensing current magnetic field occurs. Thus, change in the magnetization direction of the free magnetic layer before and after a sensing current is applied in the magnetic detecting element can be suppressed. The orthogonal state between the free magnetic layer and the pinned magnetic layer is maintained even when a sensing current in the same direction as that before the occurrence is applied in the magnetic detecting element wherein pin inversion occurred, and the output asymmetry is maintained suitably.
    Type: Grant
    Filed: July 28, 2005
    Date of Patent: July 8, 2008
    Assignee: TDK Corporation
    Inventors: Tomohiro Yamashita, Naoya Hasegawa, Eiji Umetsu, Ryo Nakabayashi, Akira Takahashi
  • Publication number: 20080151438
    Abstract: The invention provides a magnetoresistive element including a seed layer having a flat surface, which makes it possible to improve the flatness of all of the elements. A seed layer is formed in a two-layer structure of a first seed layer that is formed on a lower shield layer and a second seed layer that is formed underneath an anti-ferromagnetic layer, and the second seed layer is formed of ruthenium (Ru). According to this structure, the flatness of the surface of the seed layer is improved, which makes it possible to improve the flatness of interfaces between layers of an element formed on the seed layer. As a result, it is possible to manufacture a magnetoresistive element having a high dielectric breakdown voltage and high operational reliability.
    Type: Application
    Filed: November 28, 2007
    Publication date: June 26, 2008
    Inventors: Kenichi Tanaka, Eiji Umetsu, Kazuaki Ikarashi, Kota Asatsuma
  • Publication number: 20080145523
    Abstract: A nonmagnetic material-noncontact layer forming a fixed magnetic layer is formed using CoFe, a nonmagnetic material-contact layer is formed using Co, and an NOL (Nano-Oxide Layer) is provided between the nonmagnetic material-noncontact layer and the nonmagnetic material-contact layer. In addition, the average film thickness of the nonmagnetic material-contact layer is set in the range of 16 to 19 ?. Accordingly, compared to a three-layered structure composed of CoFe, an NOL, and CoFe or a three-layered structure composed of Co, an NOL, and Co, which has been conventionally used, the rate (?R/R) of change in resistance and the unidirectional exchange bias magnetic field (Hex*) can both be improved.
    Type: Application
    Filed: February 19, 2008
    Publication date: June 19, 2008
    Inventors: Kazuaki Ikarashi, Naoya Hasegawa, Fumihito Koike, Eiji Umetsu
  • Patent number: 7369372
    Abstract: An exchange-coupled film includes a ferromagnetic layer and an antiferromagnetic layer disposed on each other, the magnetization direction of the ferromagnetic layer being pinned in one direction by an exchange coupling magnetic field generated at the interface between the ferromagnetic layer and the antiferromagnetic layer, wherein the antiferromagnetic layer is composed of IrzMn100-z (wherein 2 atomic percent?z?80 atomic percent), the ferromagnetic layer has a two-layer structure including a CoyFe100-y layer having a face-centered cubic structure (wherein 80 atomic percent?y?100 atomic percent), the CoyFe100-y layer being in contact with the antiferromagnetic layer, and an FexCo100-x layer (wherein x?30 atomic percent), the FexCo100-x layer being disposed on the CoyFe100-y layer, and the thickness of the FexCo100-x layer is 30% to 90% of the total thickness of the ferromagnetic layer.
    Type: Grant
    Filed: November 8, 2005
    Date of Patent: May 6, 2008
    Assignee: Alps Electric Co., Ltd
    Inventors: Kazuaki Ikarashi, Naoya Hasegawa, Eiji Umetsu, Kazumi Matsuzaka, Takuya Seino
  • Patent number: 7365948
    Abstract: An exchange-coupled film includes a seed layer, an antiferromagnetic layer, and a ferromagnetic layer. The seed layer is formed at a thickness that is larger than the critical thickness, and the thickness of the seed layer is then decreased by etching so as to be smaller than or equal to the critical thickness. Thereby, a crystalline phase which extends through the seed layer from the upper surface to the lower surface can be formed, and/or the average size, in a direction parallel to the layer surface, of the crystal grains in the seed layer can be set to be larger than the thickness of the seed layer. Consequently, a large exchange coupling magnetic field Hex can be generated between the antiferromagnetic layer and the ferromagnetic layer.
    Type: Grant
    Filed: July 21, 2004
    Date of Patent: April 29, 2008
    Assignee: Alps Electric Co., Ltd
    Inventors: Ryou Nakabayashi, Eiji Umetsu, Naoya Hasegawa
  • Patent number: 7362546
    Abstract: A fixed magnetic layer contains a first magnetic layer formed on a non-magnetic metal layer. The non-magnetic metal layer is composed of an X—Mn alloy (where X is selected from Pt, Pd, Ir, Rh, Ru, Os, Ni, and Fe). While atoms forming the first magnetic layer and atoms forming the non-magnetic metal layer are being aligned with each other, strains are generated in the individual crystal structures. By generating the strain in the crystal structure of the first magnetic layer, the magnetostriction constant ? is increased. As a result, a magnetic sensor having a large magnetoelastic effect can be provided.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: April 22, 2008
    Assignee: Alps Electric Co., Ltd
    Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Yosuke Ide, Masahiro Oshima
  • Publication number: 20080088987
    Abstract: An exchange-coupled film includes a seed layer, an antiferromagnetic layer, and a ferromagnetic layer. The seed layer is formed at a thickness that is larger than the critical thickness, and the thickness of the seed layer is then decreased by etching so as to be smaller than or equal to the critical thickness. Thereby, a crystalline phase which extends through the seed layer from the upper surface to the lower surface can be formed, and/or the average size, in a direction parallel to the layer surface, of the crystal grains in the seed layer can be set to be larger than the thickness of the seed layer. Consequently, a large exchange coupling magnetic field Hex can be generated between the antiferromagnetic layer and the ferromagnetic layer.
    Type: Application
    Filed: July 6, 2007
    Publication date: April 17, 2008
    Inventors: Ryou Nakabayashi, Eiji Umetsu, Naoya Hasegawa
  • Publication number: 20080074805
    Abstract: A tunnel magnetoresistive sensor includes a pinned magnetic layer, an insulating barrier layer formed of Mg—O, and a free magnetic layer. A barrier-layer-side magnetic sublayer constituting at least part of the pinned magnetic layer and being in contact with the insulating barrier layer includes a first magnetic region formed of CoFeB or FeB and a second magnetic region formed of CoFe or Fe. The second magnetic region is disposed between the first magnetic region and the insulating barrier layer.
    Type: Application
    Filed: September 19, 2007
    Publication date: March 27, 2008
    Inventors: Kazuaki Ikarashi, Eiji Umetsu, Kenichi Tanaka, Kazumasa Nishimura, Masamichi Saito, Yosuke Ide, Ryo Nakabayashi, Yoshihiro Nishiyama, Hidekazu Kobayashi, Naoya Hasegawa
  • Publication number: 20080068767
    Abstract: An exchange-coupled film includes a seed layer, an antiferromagnetic layer, and a ferromagnetic layer. The seed layer is formed at a thickness that is larger than the critical thickness, and the thickness of the seed layer is then decreased by etching so as to be smaller than or equal to the critical thickness. Thereby, a crystalline phase which extends through the seed layer from the upper surface to the lower surface can be formed, and/or the average size, in a direction parallel to the layer surface, of the crystal grains in the seed layer can be set to be larger than the thickness of the seed layer. Consequently, a large exchange coupling magnetic field Hex can be generated between the antiferromagnetic layer and the ferromagnetic layer.
    Type: Application
    Filed: November 21, 2007
    Publication date: March 20, 2008
    Inventors: Ryou Nakabayashi, Eiji Umetsu, Naoya Hasegawa
  • Publication number: 20080024120
    Abstract: A magnetic sensor uses a magnetoresistance element which can be driven in a stable manner with a dipole irrespective of a polarity of an external magnetic field. A resistance value R of first magnetoresistance elements varies, and a resistance value of second magnetoresistance elements does not vary with a variation in magnetic field magnitude of the external magnetic field H1 in the positive direction. A resistance value R of second magnetoresistance elements varies and a resistance value of first magnetoresistance elements does not vary with a variation in magnetic field magnitude of the external magnetic field H2 in the negative direction. Accordingly, the magnetic sensor can be driven in a stable manner with a dipole irrespective of the polarity of the external magnetic field.
    Type: Application
    Filed: February 26, 2007
    Publication date: January 31, 2008
    Applicant: ALPS ELECTRIC CO., LTD.
    Inventors: Shinichi Sasaki, Kiyoshi Sato, Naoya Hasegawa, Yoshito Sasaki, Eiji Umetsu
  • Patent number: 7312959
    Abstract: At two sides of a multilayer film including a free magnetic layer, a first non-magnetic material layer, and a fixed magnetic layer, extension portions extending from the fixed magnetic layer are formed. At lower sides of the extension portions, a pair of first antiferromagnetic layers is formed with a space therebetween in a track width direction, and in addition, at upper sides of the extension portions, a pair of second antiferromagnetic layers is formed with a space therebetween in the track width direction.
    Type: Grant
    Filed: September 21, 2004
    Date of Patent: December 25, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Ryou Nakabayashi, Eiji Umetsu, Naoya Hasegawa
  • Patent number: 7312960
    Abstract: A magnetic sensing element is provided in which the magnetization of a pinned magnetic layer is pinned by a uniaxial anisotropy of the pinned magnetic layer itself. A nonmagnetic layer for increasing the coercive force of the pinned magnetic layer is disposed adjacent to the pinned magnetic layer at the opposite side of a nonmagnetic conductive layer. Specifically, the nonmagnetic layer is composed of, for example, Cu. In addition, the thickness of the nonmagnetic layer is adequately controlled.
    Type: Grant
    Filed: March 3, 2005
    Date of Patent: December 25, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Kazumi Matsuzaka, Eiji Umetsu, Naoya Hasegawa
  • Patent number: 7310208
    Abstract: A first magnetic sublayer constituting a pinned magnetic layer is provided in contact with a first magnetostriction-enhancing layer to increase the magnetostriction constant of the first magnetic sublayer. In addition, a nonmagnetic intermediate sublayer constituting the pinned magnetic layer is made of a material having a lattice constant larger than that of Ru, such as a Ru—X alloy, to distort the crystal structures of the first magnetic sublayer and a second magnetic sublayer each in contact with the nonmagnetic intermediate sublayer, increasing the magnetostriction constants of the first magnetic sublayer and the second magnetic sublayer.
    Type: Grant
    Filed: June 20, 2005
    Date of Patent: December 18, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito, Eiji Umetsu
  • Patent number: 7283335
    Abstract: In a magnetic detecting element, ferromagnetic layers are formed on both side portions of a free magnetic layer through nonmagnetic intermediate layers, and second antiferromagnetic layers are formed on the ferromagnetic layers with a spacing greater than the spacing between the ferromagnetic layers in the track width direction. Also, in both side portions of the element, the ferromagnetic layers have portions extending from the inner end surfaces of the respective second antiferromagnetic layers toward the center in the track width direction. Furthermore, electrode layers are formed on the second antiferromagnetic layers and on the extending portions of the ferromagnetic layers. It is thus possible to improve reproduced output, and suppress widening of an effective reproducing track width to appropriately suppress the occurrence of side reading.
    Type: Grant
    Filed: May 6, 2003
    Date of Patent: October 16, 2007
    Assignee: Alps Electric Co., Ltd
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Patent number: 7268984
    Abstract: A CPP magnetic detecting element having a pinned magnetic layer whose magnetization is fixed by its uniaxial anisotropy in a structure that CIP magnetic detecting elements do not allow. In the CPP magnetic detecting element, the upper and lower surfaces of a pinned magnetic layer having an artificial ferrimagnetic structure are disposed between a magnetostriction-enhancing layer made of a nonmagnetic metal and a nonmagnetic material layer having a higher lattice constant than Cu. CPP magnetic detecting elements allow this structure without reducing the variation in resistance per unit area ?R·A. Thus, the magnetostriction coefficient of the pinned magnetic layer can be increased from above and below, thereby more firmly fixing the magnetization of the pinned magnetic layer.
    Type: Grant
    Filed: June 20, 2005
    Date of Patent: September 11, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito, Eiji Umetsu
  • Patent number: 7268978
    Abstract: A CPP magnetic detecting element having a pinned magnetic layer whose magnetization is fixed by its uniaxial anisotropy in a structure that CIP magnetic detecting elements do not allow. In the CPP magnetic detecting element, the upper and lower surfaces of a pinned magnetic layer is disposed between nonmagnetic metal magnetostriction-enhancing layers. CPP magnetic detecting elements allow this structure without degrading the GMR effect. Thus, the magnetostriction coefficient of the pinned magnetic layer can be increased from above and below to produce an appropriate magnetoelasticity. Consequently, the magnetization of the pinned magnetic layer can be more firmly fixed.
    Type: Grant
    Filed: June 20, 2005
    Date of Patent: September 11, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito, Eiji Umetsu
  • Patent number: 7268983
    Abstract: A magnetic sensing device is presented that has a multilayer material with a pinned magnetic layer, a nonmagnetic material layer, and a free magnetic layer. The pinned magnetic layer is a composite with a nonmagnetic intermediate layer and magnetic thin-film layers separated from each other by the nonmagnetic intermediate layer. A first nonmagnetic magnetostriction-enhancing layer is on the pinned magnetic layer and contacts a first thin-film layer placed farthest from the nonmagnetic material layer. At least one of the magnetic thin-film layers has a composite structure with a second nonmagnetic magnetostriction-enhancing layer and magnetic layers separated from each other by the second magnetostriction-enhancing layer. All of the magnetic layers are magnetized in the same direction antiparallel to the adjacent magnetic thin-film layer. At least some crystals of the first and second magnetostriction-enhancing layers and the first thin-film layer/magnetic layers are epitaxial or heteroepitaxial.
    Type: Grant
    Filed: June 20, 2005
    Date of Patent: September 11, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito, Eiji Umetsu