Patents by Inventor Ryoichi Nakatani

Ryoichi Nakatani 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: 5290629
    Abstract: A ferromagnetic film which comprises ferromagnetic metal in which an oxide phase is present, a method for producing it, and a magnetic head in which said ferromagnetic film is used are disclosed. The ferromagnetic metal includes iron and cobalt and the oxide phase contains preferably at least one element selected from IVa, Va and VIa group elements.
    Type: Grant
    Filed: January 8, 1991
    Date of Patent: March 1, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Toshio Kobayashi, Ryoichi Nakatani, Hitoshi Nakamura, Nagatugu Koiso
  • Patent number: 5287237
    Abstract: In order to prevent generation of Barkhausen noise of a magnetoresistance-effect element, a thin antiferromagnetic film formed of Fe-Mn-X alloy containing a third alloying element X (which serves to improve corrosion resistance of Fe-Mn alloy) by 0.1 to 20 atomic % is disposed in adjacent to a thin permalloy film. The element X is selected from the group consisting of Ir, Ru, Zr, Nb, Si, Ge, V, Co, Pt and Pd. It is particularly recommended to employ Ir of 4 to 15 atomic % or Ru of 5.5 to 15 atomic % as the element X. When one or more alloying element selected from Ru, Rh, Pt, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ni, Cu, Al, Si and Ge is added to Fe and Mn which are essential components of the Fe-Mn-X alloy in addition to the element X, corrosion resistance of the alloy is improved more sufficiently.
    Type: Grant
    Filed: March 12, 1991
    Date of Patent: February 15, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Noboru Shimizu, Hideo Tanabe, Ryoichi Nakatani, Isamu Yuito, Naoki Koyama
  • Patent number: 5247415
    Abstract: A magnetic head has a main magnetic path forming film forming an operation gap, and an auxiliary magnetic path forming film for complementing said main magnetic path forming film. The auxiliary magnetic path forming film is disposed behind the gap depth of said magnetic core and magnetically coupled to the main magnetic path forming film. The main magnetic path forming film has a direction of easy magnetization perpendicular to the direction of depth of the operation gap, while the auxiliary magnetic path forming film has a direction of easy magnetization which coincides with the direction in which said magnetic head opposes the recording medium.
    Type: Grant
    Filed: November 24, 1992
    Date of Patent: September 21, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Noriyuki Kumasaka, Takeo Yamashita, Toshio Kobayashi, Ryoichi Nakatani, Shigekazu Otomo
  • Patent number: 4935311
    Abstract: Disclosed is a magnetic multilayered film in which layers of Fe or of an alloy containing Fe as an essential constituent are laminated together with intermediate layers of a nonmagnetic metal. In an embodiment of the magnetic multilayered film, each of the Fe layers or each of the Fe alloy layers is epitaxially grown on at least part of each of the intermediate layers of the nonmagnetic metal. A magnetic head having the magnetic multilayered film is also disclosed. The nonmagnetic metal is at least one of those selected from the group consisting of V, Cr, Cu, Nb, W, Al and Pt.
    Type: Grant
    Filed: April 13, 1988
    Date of Patent: June 19, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Toshio Kobayashi, Shigekazu Otomo, Noriyuki Kumasaka, Noritoshi Saito
  • Patent number: 4935314
    Abstract: An anti-corrosion ferromagnetic film and a magnetic head using the crystalline ferromagnetic film are disclosed. The anti-corrosion film contains an element interstitially soluble to iron, in addition to iron used as the main component, and further contains at least one element selected from the group consisting of Ni, Rh, Ru, Pd, Zr, Nb, Ta, Ag, Os, Ir, Pt, Au, Cr, Mo, W, Ti, Bi, V, Co and Cu, at a concentration value of 0.5 to 5 atomic percent.
    Type: Grant
    Filed: March 24, 1988
    Date of Patent: June 19, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Toshio Kobayashi, Ryoichi Nakatani, Shigekazu Otomo, Noriyuki Kumasaka
  • Patent number: 4920013
    Abstract: A magnetic multilayer structure having an increased permeability and an increased saturation magnetic flux density comprises a plurality of magnetic layers and a plurality of intermediate layers alternately laminated one upon another. Each of the magnetic layers is made of Fe, Co, Ni or an alloy containing one of Fe, Co and Ni, while each of the intermediate layers is made of a material capable of interstitially forming a solid solution with the material of the magnetic layers.
    Type: Grant
    Filed: September 23, 1987
    Date of Patent: April 24, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Toshio Kobayashi, Shigekazu Otomo, Ryoichi Nakatani, Noriyuki Kumasaka
  • Patent number: 4891278
    Abstract: A ferromagnetic thin film containing Fe as a main component and at least one additive element selected from the group consisting of Co, Ni, Ru, Rh, Pd, Os, Ir and Pt, in which the total content of the at least one additive element is not less than 0.1 at % and additive contents, a, b, c, d, e, f, g and h (at %) respectively of said Co, Ni, Ru, Rh, Pd, Os, Ir and Pt satisfy ##EQU1## The ferromagnetic thin film thus disclosed has a high saturation flux density of 18 KG or more, a magnetostriction constant close to zero, and excellent corrosion resistance. There is also disclosed a magnetic head using the above described ferromagnetic thin film in at least a part of a magnetic circuit thereof.
    Type: Grant
    Filed: February 19, 1987
    Date of Patent: January 2, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Shigekazu Otomo, Ryoichi Nakatani, Noriyuki Kumasaka, Noritoshi Saito, Toshio Kobayashi, Masahiko Fujishiro
  • Patent number: 4858049
    Abstract: A magnetic film and a magnetic head using the magnetic film are disclosed. The magnetic film is formed by adding one or more elements by 5 to 20 at. %, the elements being selected from B, N, C and P interstitially soluble to Fe to a magnetic film made of Fe or having Fe as its main component.
    Type: Grant
    Filed: June 1, 1987
    Date of Patent: August 15, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Toshio Kobayashi, Shigekazu Otomo, Ryoichi Nakatani, Noriyuki Kumasaka