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: 6995961
    Abstract: Changes of the direction of magnetization at the central region of the free magnetic layer are facilitated by using a layer of a magnetic material having a small exchange stiffness constant such as a NiaFeb layer (a and b are represented in at %, and satisfy the relation of a>80 and a+b=100) and NiFeX layer (X is at least one element selected from Mn, Cu, Zn, Ti, Al, Ge, Si, Cr, V, Sn, Ir, Ru, Nb, Sb, W, Mo, Os and Ta) for the magnetic material layer of the free magnetic layer.
    Type: Grant
    Filed: March 27, 2003
    Date of Patent: February 7, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Fumihito Koike, Eiji Umetsu, Masahiko Ishizone
  • Publication number: 20060002039
    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: Application
    Filed: June 20, 2005
    Publication date: January 5, 2006
    Inventors: Naoya Hasegawa, Masamichi Saito, Eiji Umetsu
  • Patent number: 6979500
    Abstract: A magnetic sensing element is provided, in which magnetization of a free magnetic layer is likely to fluctuate when the track width is further reduced, and thereby, the magnetic field detection sensitivity can be improved. A second free magnetic layer having a dimension W2 in the track-width direction is laminated on a first free magnetic layer having a dimension W1 in the track-width direction while the dimension W2 is larger than the dimension W1. The film thickness ta of the free magnetic layer in the track-width region A is made larger than the film thickness tb of the free magnetic layer in both side regions B and B. Consequently, the magnetic flux density in the track-width region A of the free magnetic layer resulting from the static magnetic fields generated from both the side regions B and B of the free magnetic layer can be reduced, a dead zone which occurs in the track-width region A of the free magnetic layer can be reduced, and therefore, the magnetic field detection sensitivity is improved.
    Type: Grant
    Filed: June 24, 2003
    Date of Patent: December 27, 2005
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Publication number: 20050280953
    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: Application
    Filed: June 20, 2005
    Publication date: December 22, 2005
    Inventors: Naoya Hasegawa, Masamichi Saito, Eiji Umetsu
  • Publication number: 20050280954
    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: Application
    Filed: June 20, 2005
    Publication date: December 22, 2005
    Inventors: Naoya Hasegawa, Masamichi Saito, Eiji Umetsu
  • Publication number: 20050280955
    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: Application
    Filed: June 20, 2005
    Publication date: December 22, 2005
    Inventors: Naoya Hasegawa, Masamichi Saito, Eiji Umetsu
  • Publication number: 20050276997
    Abstract: The present invention provides a magnetic detecting element including a pinned magnetic layer and a first antiferromagnetic layer which constitutes an exchange coupling film and the structures of which are optimized for properly pinning magnetization of the pinned magnetic layer, improving reproduction output and properly complying with a narrower gap, and a method of manufacturing the magnetic detecting element. The pinned magnetic layer has a synthetic ferrimagnetic structure, and the first antiferromagnetic layer has a predetermined space C formed at the center in the track width direction to produce exchange coupling magnetic fields only between the first antiferromagnetic layer and both side portions of a first magnetic layer of the pinned magnetic layer. Therefore, the magnetization of the pinned magnetic layer can be pinned, and an improvement in reproduction output and gap narrowing can be realized.
    Type: Application
    Filed: September 30, 2003
    Publication date: December 15, 2005
    Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Yosuke Ide
  • Publication number: 20050207072
    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: Application
    Filed: March 3, 2005
    Publication date: September 22, 2005
    Inventors: Kazumi Matsuzaka, Eiji Umetsu, Naoya Hasegawa
  • Patent number: 6921587
    Abstract: Disclosed are a CPP magnetic sensing element employing the exchange bias method in which a sensing current is prevented from expanding in the track width direction in the multilayer film while the magnetization of the free magnetic layer is controlled properly, side reading is effectively prevented, and read output is improved, and a method for fabricating the same. First insulating layers are disposed at both sides in the track width direction of a multilayer film, a second free magnetic layer is disposed over the multilayer film and the first insulating layers, and second antiferromagnetic layers are disposed on both side regions of the second free magnetic layer.
    Type: Grant
    Filed: June 24, 2003
    Date of Patent: July 26, 2005
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Publication number: 20050157435
    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: January 12, 2005
    Publication date: July 21, 2005
    Inventors: Kazuaki Ikarashi, Naoya Hasegawa, Fumihito Koike, Eiji Umetsu
  • Patent number: 6901652
    Abstract: A method for manufacturing magnetic sensing elements for use in magnetic sensors and hard disks. A ferromagnetic layer and a second antiferromagnetic layer are deposited on a nonmagnetic layer having a uniform thickness. The second antiferromagnetic layer is milled to form an indent. The resulting magnetic sensing element has a free magnetic layer reliably set in a single-magnetic-domain state in the track width direction.
    Type: Grant
    Filed: July 11, 2002
    Date of Patent: June 7, 2005
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Patent number: 6893734
    Abstract: A magnetic sensing element includes a laminate, the laminate including a first antiferromagnetic layer; a pinned magnetic layer, the magnetization direction thereof being pinned by the first antiferromagnetic layer; a nonmagnetic conductive layer; a free magnetic layer, the magnetization direction thereof being variable in response to an external magnetic field; a nonmagnetic interlayer; a ferromagnetic layer; and a second antiferromagnetic layer. The laminate has a recess extending through the second antiferromagnetic layer and the ferromagnetic layer, a bottom face of the recess lying in the nonmagnetic interlayer, the width of the bottom face in a track width direction being equal to a track width. The free magnetic layer is magnetized in a direction substantially orthogonal to the magnetization direction of the pinned magnetic layer as a result of magnetic coupling with the ferromagnetic layer. A method for making such a magnetic sensing element is also disclosed.
    Type: Grant
    Filed: December 14, 2001
    Date of Patent: May 17, 2005
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Kenichi Tanaka, Yosuke Ide
  • Patent number: 6885528
    Abstract: A magnetic sensing element comprising a composite film having a center portion and two side portions, a second antiferromagnetic layer, a chromium nonmagnetic layer, and third antiferromagnetic layers is provided. The composite film comprises a first antiferromagnetic layer; a pinned magnetic layer on the first antiferromagnetic layer; a nonmagnetic material layer on the pinned magnetic layer; and a free magnetic layer on the nonmagnetic material layer. The second antiferromagnetic layer is disposed on the free magnetic layer. The chromium nonmagnetic layer is disposed on the second antiferromagnetic layer at the center portion. The third antiferromagnetic layers are disposed on the second antiferromagnetic layer at the two side portions. The magnetization direction in the two side portions of the free magnetic layer is pinned in the track width direction and the magnetization direction in the center portion is rotatable in response to external magnetic fields.
    Type: Grant
    Filed: April 23, 2003
    Date of Patent: April 26, 2005
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Publication number: 20050073777
    Abstract: The present invention provides a magnetic head including a magnetic flux guide layer for effectively inducing an external magnetic field in a free magnetic layer. A magnetic domain control layer is formed in a space below the magnetic flux guide layer and in front of a multilayer film near a surface facing a recording medium. Therefore, the shape of the magnetic flux guide layer can be made substantially flat to improve flux transmission efficiency. Also, the magnetization of the magnetic flux guide layer is controlled by laminating the magnetic flux guide layer on the magnetic domain control layer. Therefore, the magnetic domain control layer can be formed in a substantially flat thin film to stabilize a bias magnetic field to be supplied to the magnetic flux guide layer. Furthermore, the gap length of the magnetic head can be kept short.
    Type: Application
    Filed: June 17, 2003
    Publication date: April 7, 2005
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Publication number: 20050068694
    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: Application
    Filed: September 21, 2004
    Publication date: March 31, 2005
    Inventors: Ryou Nakabayashi, Eiji Umetsu, Naoya Hasegawa
  • Patent number: 6870715
    Abstract: A magnetoresistive element exhibiting good external magnetic field detection characteristics is provided. The magnetoresistive element includes a laminate comprising a nonmagnetic conductive layer, first and second ferromagnetic layer sandwiching the nonmagnetic conductive layer, and a first antiferromagnetic layer for pinning the magnetization direction of the first ferromagnetic layer, deposited on the face of the first ferromagnetic layer opposite the face in contact with the nonmagnetic conductive layer. Bias layers for applying a bias magnetic field to the second ferromagnetic layer are provided respectively on two ends of the laminate. Each bias layer comprises second and third antiferromagnetic layers and a third ferromagnetic layer sandwiched by the second and third antiferromagnetic layers so as to magnetically couple with the second and third antiferromagnetic layer. Two end faces of the second ferromagnetic layer come into contact with the third ferromagnetic layers.
    Type: Grant
    Filed: September 21, 2001
    Date of Patent: March 22, 2005
    Assignee: Alps Electric Co., Ltd.
    Inventor: Eiji Umetsu
  • Patent number: 6856494
    Abstract: The present invention provides a spin-valve type thin film magnetic element that is able to certainly align the magnetization direction of the free magnetic layer in one direction by improving the exchange coupling magnetic field generated between the bias layers and ferromagnetic layer, and is able to reduce the thickness of the bias layer to be smaller than the thickness of the bias layer of the conventional spin-valve type thin film magnetic element for obtaining the same magnitude of the exchange coupling magnetic layer as that in the conventional spin-valve type thin film magnetic element.
    Type: Grant
    Filed: June 20, 2001
    Date of Patent: February 15, 2005
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masahiro Ooshima, Eiji Umetsu, Masamichi Saito, Kenichi Tanaka, Naoya Hasegawa, Yosuke Ide
  • Publication number: 20050024793
    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 21, 2004
    Publication date: February 3, 2005
    Inventors: Ryou Nakabayashi, Eiji Umetsu, Naoya Hasegawa
  • Publication number: 20050018363
    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: Application
    Filed: August 24, 2004
    Publication date: January 27, 2005
    Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Yosuke Ide, Masahiro Oshima
  • Patent number: 6831817
    Abstract: A first magnetic layer includes an area which contains an element X (e.g., Cr) and is present in position toward the side of a nonmagnetic intermediate layer from the side near an opposite surface of the first magnetic layer away from an interface between the first magnetic layer and the nonmagnetic intermediate layer, and an area which is partly located in a region from the interface between the first magnetic layer and the nonmagnetic intermediate layer toward the opposite surface of the first magnetic layer and which does not contain the element X. Such an arrangement is able to improve a resistance change rate, to increase a coupling magnetic field based on the RKKY interaction, and to realize satisfactory control of magnetization of a free magnetic layer.
    Type: Grant
    Filed: October 9, 2002
    Date of Patent: December 14, 2004
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu