Patents by Inventor Masahiro Kitada

Masahiro Kitada 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: 5719729
    Abstract: In an inductive-write, magnetoresistive-read type magnetic head having a magnetoresistive read head and an inductive write head superimposed on each other, the magnetic center of the read head is made more coincident with the physical center of the write head by a changing of a magnetization direction of a magnetoresistive element. The recording/reproducing apparatus using this magnetic head can thus have a good S/N ratio even if the track width is narrow.
    Type: Grant
    Filed: December 15, 1992
    Date of Patent: February 17, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Naoki Koyama, Yoshihiro Hamakawa, Isamu Yuitoo, Kanji Kawakami, Kazuo Shiiki, Masahiro Kitada
  • Patent number: 5521005
    Abstract: In a magnetic head whose recording and reproduction sections are separated, the magnetoresistive element constituting the reproduction head has a structure comprising a soft magnetic film, a spacer metallic film, and a magnetoresistive film and uses a high-performance soft magnetic film whose composition is Ni--Fe--Ru, Ni--Fe--Ru--M (M: fourth element), Ni--Fe--Ta or Ni--Fe--Ta--M (M: fourth element) and which has low coercivity, low magnetostriction, high specific resistance, high saturation magnetization, low magnetoresistivity and high corrosion resistance, this invention provides a recording-reproduction separation type magnetic head comprising a soft magntic bias film which is high magnetic performance, low production cost, and high corrosion resistance.
    Type: Grant
    Filed: November 25, 1992
    Date of Patent: May 28, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Noboru Shimizu, Naoki Koyama
  • Patent number: 5461526
    Abstract: A magnetoresistive read head includes a magnetoresistive layer having a central active region and end domain control regions, an electrode layer connected to both ends of the magnetoresistive layer, a pattern for providing a transverse bias to the magnetoresistive layer, a soft magnetic film provided on both sides of the magnetoresistive layer for magnetically shielding the magnetoresistive layer, and a substrate for supporting the magnetoresistive layer, pattern and soft magnetic film. A distance between the two end domain control regions of the magnetoresistive layer indicative of a length of the central active region is smaller than a distance between inner end faces of the electrode layer and the distance between the inner end faces of the magnetoresistive substantially corresponds to a read track width.
    Type: Grant
    Filed: March 24, 1993
    Date of Patent: October 24, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihiro Hamakawa, Toshio Kobayashi, Naoki Koyama, Masahiro Kitada
  • Patent number: 5401542
    Abstract: In a magnetoresistive magnetic head which has a permalloy film (2, 22) as the magnetoresistive film and also has a shunt film for applying a transverse biasing magnetic field, an Nb film (3, 23) is formed as the shunt film by the electron-beam evaporation method to increase the heat resistance of the magnetoresistive element, thus making it possible to increase the temperature at which the magnetic head is manufactured.
    Type: Grant
    Filed: February 16, 1993
    Date of Patent: March 28, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Noboru Shimizu, Hideo Tanabe, Hitoshi Nakamura
  • Patent number: 5390061
    Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magneto-resistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.
    Type: Grant
    Filed: June 5, 1991
    Date of Patent: February 14, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
  • Patent number: 5371643
    Abstract: A magnetoresistive head is fabricated with a high yield rate by preventing the electrode film from breaking down. An upper shield film is formed with an electrode separation layer and an upper gap film disposed between it and the electrode film. The electrode film is prevented from being etched when the upper shield film is subjected to ion milling as a result. Further, the upper gap film is laid on top of the electrode separation layer, and a lead is satisfactorily protected and prevented from being exposed. Thus, the upper shield film and the lead are prevented from becoming short-circuited as a result of the disconnection of the electrode film and the exposure of the lead.
    Type: Grant
    Filed: August 11, 1992
    Date of Patent: December 6, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Isamu Yuito, Makoto Morijiri, Tooru Takeura, Katsunori Ohwada, Masahiro Kitada
  • Patent number: 5337203
    Abstract: A magnetoresistive head having a structure based on a two-layer film having a first film exhibiting a magnetoresistive effect and a second film comprising Nb and at least one element selected from the group consisting of Ti, Cr, Mo, Zr, W, Pt, Re, V, Hf, Ta, Rh, Ni and Ru as an additive element.
    Type: Grant
    Filed: April 27, 1992
    Date of Patent: August 9, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Hideo Tanabe, Noboru Shimizu, Naoki Koyama, Toshio Kobayashi
  • 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: 5218497
    Abstract: A magnetic recording-reproducing apparatus is disclosed which comprises a recording inductive magnetic head, a reproducing magnetoresistive magnetic head, a read-write circuit for inputting a signal to the inductive magnetic head and for reproducing the output from the magnetoresistive magnetic head, an interface for inputting/outputting a signal between the read-write circuit and an external apparatus, and a mechanism for moving the inductive magnetic head, the magnetoresistive magnetic head and the magnetic recording medium relative to one another, wherein the information recorded on the recording medium is reproduced with an area recording density of 300 Mb/in.sup.2 or more.
    Type: Grant
    Filed: December 13, 1991
    Date of Patent: June 8, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Hideo Tanabe, Masahiro Kitada, Noboru Shimizu, Hitoshi Nakamura
  • Patent number: 5212609
    Abstract: A magnetoresistive head is disclosed. It comprises a lower gap film, a magnetoresistive film, a bias film, an electrode, an upper gap film, and upper shield film provided in sequence on a substrate. A protective film is provided under the upper shield film to prevent the upper gap film and electrode from the undesirable etching during patterning the upper shield film.
    Type: Grant
    Filed: November 15, 1991
    Date of Patent: May 18, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Isamu Yuito, Makoto Morijiri, Tooru Takeura, Naoki Koyama, Masahiro Kitada
  • Patent number: 5181149
    Abstract: A magnetic recording/reproducing head assembly comprising a first magnetic path forming member on which a coil is mounted, a second magnetic path forming member which forms a magnetic path in cooperation with the first magnetic path forming member, and a film laminate formed at a front gap portion between the first magnetic path forming member and the second magnetic path forming member. The film laminate includes a magnetic detecting element for detecting a change in a magnetic field and a soft magnetic film or films. This magnetic head assembly is prepared by forming the film laminate on a head base of the head assembly, bonding a core member to the head base with the film laminate formed thereon, and mounting a coil on the core member.
    Type: Grant
    Filed: September 18, 1989
    Date of Patent: January 19, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Masao Katsumata, Kazuhiro Momata, Kazuyoshi Adachi, Tooru Takeura, Masahiro Kitada, Yoshihisa Kamo, Toshikane Yoshimatsu
  • Patent number: 5010433
    Abstract: In a magnetoresistive magnetic head which has a permalloy film as the magnetoresistive film and also has a shunt film for applying a transverse biasing magnetic field, an Nb film having an electrical resistivity of not more than 30 .mu..OMEGA.cm is formed as the shunt film by the electron-beam evaporation method to increase the heat resistance of the magnetoresistive element, thus making it possible to increase the temperature at which the magnetic head is manufactured.
    Type: Grant
    Filed: February 16, 1989
    Date of Patent: April 23, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Noboru Shimizu, Hideo Tanabe, Hitoshi Nakamura
  • Patent number: 4907114
    Abstract: A magneto-resistive type read head has a substrate, a magnetic film exhibiting a magneto-resistive effect arranged in the widthwise direction of the track of a magnetic writing disk, and lead electrodes for feeding an electric current to the track width portion of the magnetic film for reading the signals written in the magnetic writing disk. The magneto-resistive film extends over a width wider than the track width portion and a soft magnetic thin film is formed over the magneto-resistive film on either side of the track width portion to absorb the domain wall so that the magneto-resistive film takes the single domain structure.
    Type: Grant
    Filed: June 3, 1988
    Date of Patent: March 6, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Kazuo Shiiki, Masahiro Kitada, Hideo Tanabe, Hitoshi Nakamura, Isamu Yuito, Hisashi Takano
  • Patent number: 4841399
    Abstract: The use of a pure zirconium film as a shunt film in a magnetoresistive head having a permalloy film as a magnetoresistive film and a shunt film for application of a transverse biasing magnetic field serves to improve the heat resistance of the magnetoresistive element and allows an increase in the temperature used in the process for producing a magnetic head.
    Type: Grant
    Filed: December 1, 1986
    Date of Patent: June 20, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Noboru Shimizu, Hideo Tanabe, Hitoshi Nakamura, Tetsuo Kobayashi, Tooru Takeura, Kazuhiro Momata
  • Patent number: 4816948
    Abstract: Magneto-resistive head comprising a magneto-resistive film, and a soft magnetic film disposed at one side of said magneto-resistive film, which soft magnetic film is magnetized by electric current flowing through the magneto-resistive film, to which a bias magnetic field is applied by the magnetization of the soft magnetic film, whereby they are so structured that 0.7.times.B.sub.SMR .times.T.sub.MR <B.sub.SSF .times.T.sub.SF is satisfied, where T.sub.MR and B.sub.SMR represent the thickness and the saturated magnetic flux density, respectively, of the magneto-resistive film and T.sub.SF and B.sub.SSF represent the thickness and the saturated magnetic flux density, respectively, of the soft magnetic film.
    Type: Grant
    Filed: February 10, 1987
    Date of Patent: March 28, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihisa Kamo, Masahiro Kitada
  • Patent number: 4814919
    Abstract: A soft-film-bias type magnetoresistive device is disclosed in which a high-permeability magnetic film, an insulating film and a permalloy film are formed on a substrate in this order, and first, second and third electrodes, which are parallel to each other, are provided on the permalloy film, to form a differential type magnetoresistive device. In this magnetoresistive device, a bias magnetic field which is generated and applied to the permalloy film between the first and second electrodes, is opposite in direction to a bias magnetic field which is generated and applied to the permalloy film between the second and third electrodes.
    Type: Grant
    Filed: November 24, 1987
    Date of Patent: March 21, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Hideo Tanabe, Noboru Shimizu, Yoshihisa Kamo, Hitoshi Nakamura, Tooru Takeura
  • Patent number: 4783711
    Abstract: In a magnetoresistive sensor having a magnetoresistive effect element which is held between two sheets of high permeability magnetic ferrite with insulating layers interposed between them, a ferromagnetic metal film is provided adherently to the high permeability magnetic ferrite between the ferrite and the insulating layer, a rise in temperature of the magnetoresistive effect element thereby being held down and a reproduced waveform being made sharp, and thus the characteristics of the element being improved with the life thereof prolonged.
    Type: Grant
    Filed: June 27, 1986
    Date of Patent: November 8, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Hideo Tanabe, Noboru Shimizu, Hitoshi Nakamura, Kazuhiro Momata, Shigeyoshi Kato, Tooru Takeura, Tetsuo Kobayashi
  • Patent number: 4769093
    Abstract: A magnetoresistive device includes a magnetoresistive film made of permalloy alloy. This thin film is formed on a substrate by sputtering or vapor deposition method. Thereafter, the thin film is heated to a temperature between 200.degree. C. and 350.degree. C. by flowing an electric current therethrough or irradiating the thin film with an electron or laser beam. It is desirable that the heat treatment is effected in an alternating magnetic field. The permalloy alloy may contain at least one element including Rh, Ru, Mo, Cr and V.
    Type: Grant
    Filed: June 24, 1987
    Date of Patent: September 6, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Hideo Tanabe, Noboru Shimizu
  • Patent number: 4663684
    Abstract: Disclosed is a magnetic transducer using a magnetoresistance effect, comprising a magnetoresistive film, a hard magnetic film for applying a transverse biasing magnetic field thereto, and a conductive film through which current for applying the transverse biasing magnetic field to the magnetoresistive film flows. The conductive film may be either in electrical contact with or in electrical insulation from the magnetoresistive film. In this magnetic transducer, even when the heights of the respective constituents have changed, the transverse biasing magnetic field to be applied does not change considerably, and an optimum bias field strength is readily attained.
    Type: Grant
    Filed: January 25, 1985
    Date of Patent: May 5, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihisa Kamo, Naoki Sato, Masahiro Kitada, Tooru Takeura
  • Patent number: 4663607
    Abstract: A magnetroresistive element formed by laminating a plurality of metallic magnetoresistance effect films having magnetostriction of different signs on a substrate. The magnetoresistive element can be formed to exhibit zero magnetostriction or to exhibit magnetostriction of any desired value. Further, the magnetoresistive element exhibits magnetostriction that changes little with the change in the film composition. The metallic magnetoresistance effect films preferably have positive and negative magnetostriction with an absolute value not greater than 15.times.10.sup.-6.
    Type: Grant
    Filed: May 28, 1985
    Date of Patent: May 5, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Masahiro Kitada, Hideo Tanabe, Noboru Shimizu, Hiroshi Tsuchiya, Masao Katsumata