Patents by Inventor Migaku Takahashi

Migaku Takahashi 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: 20090168270
    Abstract: In comparison with conventional exchange-coupled elements, the exchange-coupled element of the present invention has greater unidirectional magnetization anisotropy. The exchange-coupled element comprises: an ordered antiferromagnetic layer; and a pinned magnetic layer being exchange-coupled with the ordered antiferromagnetic layer, the pinned magnetic layer having unidirectional magnetization anisotropy. The pinned magnetic layer is constituted by a first pinned magnetic layer having a composition, which can have a face-centered cubic lattice structure, and a second pinned magnetic layer having a composition, which can have a body-centered cubic lattice structure.
    Type: Application
    Filed: December 23, 2008
    Publication date: July 2, 2009
    Applicants: FUJITSU LIMITED, TOHOKU UNIVERSITY
    Inventors: Migaku Takahashi, Masakiyo Tsunoda, Koujiro Komagaki, Yuji Uehara
  • Publication number: 20090169915
    Abstract: The method of the present invention provides a magnetoresistance effect element, which is capable of having a high MR ratio, corresponding to high density recording and being suitably applied to a magnetoresistance device even though a barrier layer is thinned to reduce resistance of the magnetoresistance effect element. The method of producing the magnetoresistance effect element, which includes the barrier layer composed of an oxidized metal, a first magnetic layer contacting one of surfaces of the barrier layer and a second magnetic layer contacting the other surface thereof, comprises the steps of: laminating the barrier layer on the first magnetic layer with using a target composed of the oxidized metal; and laminating the second magnetic layer on the barrier layer. The barrier layer is annealed before laminating the second magnetic layer thereon.
    Type: Application
    Filed: December 19, 2008
    Publication date: July 2, 2009
    Applicants: FUJITSU LIMITED, TOHOKU UNIVERSITY
    Inventors: Migaku Takahashi, Masakiyo Tsunoda, Koujiro Komagaki, Yuji Uehara, Kazuyuki Sunaga
  • Publication number: 20090147401
    Abstract: The present invention provides a magnetic recording medium capable of recording or reproducing high-density information by reducing the grain size of a perpendicular magnetic recording layer and improving vertical orientation, a method of manufacturing the same, and a magnetic recording/reproducing apparatus. The perpendicular magnetic recording medium includes: a non-magnetic substrate; and at least an soft magnetic layer, an under layer, an intermediate layer, and a perpendicular magnetic recording film that are formed on the non-magnetic substrate. At least one layer of the intermediate layer is made of an alloy material of an element having an fcc structure and an element having a bcc structure or an hcp structure, and has both a crystal structure having (111) orientation and an irregular layer lattice (stacking fault) caused by a mixture of the fcc structure and the bcc structure.
    Type: Application
    Filed: May 5, 2007
    Publication date: June 11, 2009
    Inventors: Migaku Takahashi, Shin Saito, Tomoyuki Maeda, Akihiko Takeo, Yuzo Sasaki, Ryuji Sakaguchi
  • Publication number: 20090034119
    Abstract: The invention provides a perpendicular recording medium with high recording density, and a magnetic recording and reproducing apparatus, by improving the function of magnetic anisotropy of a soft magnetic underlayer. The perpendicular recording medium has at least a soft magnetic underlayer and a perpendicular magnetic recording layer on a non-magnetic substrate, wherein when Ku? (erg/cm3) is defined as a perpendicular magnetic anisotropic energy, and Ms (emu/cm 3) is defined as a saturation magnetization of the soft magnetic underlayer, Ku? of the soft magnetic underlayer has a negative value and Ku?<?2?Ms2. As a result, the easy axis of a magnetization of a soft magnetic underlayer is oriented strongly in the substrate surface plane, which is effective to suppress the WATE phenomena and spike noise.
    Type: Application
    Filed: March 29, 2006
    Publication date: February 5, 2009
    Applicants: Tohoku University, SHOWA DENKO K.K., Kabushiki Kaisha Toshiba
    Inventors: Migaku Takahashi, Masahiro Oka, Akira Kikitsu
  • Publication number: 20080261080
    Abstract: A magnetic recording medium includes as formed on a non-magnetic substrate, a seed layer, an underlayer of a bcc structure-having Cr alloy, an interlayer of an hcp structure-having Ru alloy, a lower recording layer of a Co—Cr—Pt—B base alloy, an upper recording layer having the same alloying base components as those of the lower recording layer, a larger B atom concentration and having a larger Co atom concentration to Cr atom concentration ratio, and a protective layer. The lower recording layer includes a first and a second lower recording layer. When the B atom concentration in the first lower recording layer is B1 and that of the second lower recording layer is B2, then B1<B2, and when the Co atom concentration to Cr atom concentration ratio in the first lower recording layer is (Co/Cr)1, and that of the second lower recording layer is (Co/Cr)2, then (Co/Cr)1<(Co/Cr)2.
    Type: Application
    Filed: December 21, 2007
    Publication date: October 23, 2008
    Applicants: FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD., TOHOKU UNIVERSITY
    Inventors: Hirohisa OHYAMA, Tuqiang Li, Daiji Hasegawa, Shin Saito, Migaku Takahashi
  • Publication number: 20080180857
    Abstract: The tunnel magnetoresistance effect film is a highly practical tunnel magnetoresistance effect film having a characteristic of serviceable negative MR ratio, which can be used at room temperature. The tunnel magnetoresistance effect film comprises: a tunnel barrier layer; and magnetic layers sandwiching the tunnel barrier layer. One of the magnetic layers is composed of FeN.
    Type: Application
    Filed: November 29, 2007
    Publication date: July 31, 2008
    Applicant: Fujitsu Limited
    Inventors: Migaku Takahashi, Masakiyo Tsunoda, Kojiro Komagaki
  • Publication number: 20080180860
    Abstract: In the magnetic thin film, a magnetization direction of a ferromagnetic layer, e.g., a pinned layer, can be securely fixed. The magnetic thin film comprises: an antiferromagnetic layer; and the ferromagnetic layer. The antiferromagnetic layer is composed of a manganic antiferromagnetic material, and a manganese (Mn) layer is formed between the antiferromagnetic layer and the ferromagnetic layer.
    Type: Application
    Filed: November 29, 2007
    Publication date: July 31, 2008
    Applicant: Fujitsu Limited
    Inventors: Migaku Takahashi, Masakiyo Tsunoda, Kojiro Komagaki
  • Publication number: 20080118781
    Abstract: Perpendicular magnetic recording media enabling high-density recording and reproduction of information, as well as a production process thereof, and a magnetic recording and reproducing apparatus, are provided. Perpendicular magnetic recording media, having at least a soft magnetic underlayer and perpendicular magnetic recording layer on a disc-shaped nonmagnetic substrate, in which the soft magnetic underlayer has at least two soft magnetic layers, and Ru or Re between the two soft magnetic layers, are provided; the easy axis of magnetization of the soft magnetic underlayer has a desired direction; the easy axis of magnetization of the soft magnetic underlayer is substantially distributed in a direction except a radial direction of the nonmagnetic substrate, and, the bias magnetic field of the antiferromagnetic coupling in the direction of the easy axis of magnetization of the soft magnetic underlayer is 10 Oersteds (790 A/m) or greater.
    Type: Application
    Filed: January 31, 2006
    Publication date: May 22, 2008
    Applicants: Tohoku University, SHOWA DENKO K.K., Kabushiki Kaisha Toshiba
    Inventors: Migaku Takahashi, Masahiro Oka, Akira Kikitsu
  • Publication number: 20080037407
    Abstract: One object of the present invention is to provide a perpendicular magnetic recording medium having a high coercive force by annealing, and in order to achieve the object, the present invention provides a method for manufacturing a perpendicular magnetic recording medium comprising a magnetic recording layer deposited on a non-magnetic substrate, in which at least a magnetic layer containing Co and a diffusive layer are stacked each other, and the stacked layers are annealed to produce a magnetic recording layer.
    Type: Application
    Filed: September 15, 2005
    Publication date: February 14, 2008
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Migaku Takahashi, Masahiro Oka, Akira Kikitsu
  • Patent number: 7297423
    Abstract: A PCB that can transmit a high frequency signal of a GHz band with a low loss includes an insulator and magnetic nanoparticles dispersed in the insulator.
    Type: Grant
    Filed: February 25, 2005
    Date of Patent: November 20, 2007
    Assignees: Sony Corporation, Migaku Takahashi
    Inventors: Mikihisa Mizuno, Yuichi Sasaki, Makoto Inoue, Kenji Yazawa, Migaku Takahashi, Yasuo Tateno, Teiichi Miyauchi
  • Publication number: 20070259214
    Abstract: The invention provides a perpendicular magnetic recording medium in which the recording density is greatly increased with little deviation of the crystal structure. A perpendicular magnetic recording medium has at least a soft magnetic under layer, an orientation control layer, a perpendicular magnetic layer, and a protective layer, which are formed on a nonmagnetic substrate, the orientation control layer consisting of a plurality of layers including a seed layer and an intermediate layer from the substrate side. Preferably, the seed layer and the intermediate layer each have a hexagonal close-packed (hcp) structure, and the average grain size of the seed layer is between 8 nm and 20 nm. The main component of the seed layer is preferably Mg, and the main component of the intermediate layer is preferably Ru.
    Type: Application
    Filed: October 28, 2005
    Publication date: November 8, 2007
    Applicants: MIGAKU TAKAHASHI, SHOWA DENKO K.K., KABUSHIKI KAISHA TOSHIBA
    Inventors: Migaku Takahashi, Masahiro Oka, Akira Kikitsu
  • Publication number: 20070230233
    Abstract: An information recording apparatus comprises a plurality of fine particles forming an array on a plane in close proximity of each other, each of the plural particles including a ferromagnetic metal, a light-emitting device for exciting a near-field light, and a photo-electric conversion element for detecting a near-field light traveled along the fine particles.
    Type: Application
    Filed: March 30, 2007
    Publication date: October 4, 2007
    Inventors: Migaku Takahashi, Masakiyo Tsunoda, Shin Saito, Tomoyuki Ogawa, Itaru Fujimura, Shigeyoshi Misawa, Toshiyuki Kawasaki
  • Publication number: 20070141401
    Abstract: According to one embodiment, a multilayered underlayer including a first underlayer containing Cu aligned in a (111) plane and a second underlayer formed on the Cu underlayer and containing Cu and nitrogen as main components is formed.
    Type: Application
    Filed: December 19, 2006
    Publication date: June 21, 2007
    Applicants: KABUSHIKI KAISHA TOSHIBA, TOHOKU UNIVERSITY, SHOWA DENKO K.K.
    Inventors: Tomoyuki Maeda, Migaku Takahashi, Masahiro Oka
  • Publication number: 20070107739
    Abstract: A working rod with a tip end extending into a vacuum process chamber and moving in the axial direction, two static-pressure gas bearings supporting the rod in the non-contact manner, and an internal moving body of a magnet coupling type driving mechanism driving the rod are housed in a rod housing cylindrical portion leading to the vacuum process chamber, and an exhaust portion by suction is provided at a part of the rod housing cylindrical portion so that the pressure of the rod housing cylindrical portion is lowered than the pressure of the vacuum process chamber by the exhaust from the exhaust portion.
    Type: Application
    Filed: October 25, 2006
    Publication date: May 17, 2007
    Applicants: SMC Corporation, Tohoku University
    Inventors: Soichi Sato, Takashi Abe, Eiko Miyasato, Migaku Takahashi, Masakiyo Tsunoda
  • Publication number: 20070110347
    Abstract: A first and a second static-pressure gas bearings supporting a rod at two locations in the axial direction in the non-contact manner are provided, in which the first static-pressure gas bearing is fixedly supported by a bearing housing, while the second static-pressure gas bearing is supported capable of displacement through a movable support mechanism. And this movable support mechanism has an actuator and suppresses contact of the rod with the static-pressure gas bearings by displacing the shaft center of the second static-pressure gas bearing with respect to the first static-pressure gas bearing by this actuator according to a load acting on the rod.
    Type: Application
    Filed: October 25, 2006
    Publication date: May 17, 2007
    Applicants: SMC CORPORATION, TOHOKU UNIVERSITY
    Inventors: Soichi Sato, Takashi Abe, Eiko Miyasato, Migaku Takahashi, Masakiyo Tsunoda
  • Publication number: 20050238858
    Abstract: A PCB that can transmit a high frequency signal of a GHz band with a low loss includes an insulator and magnetic nanoparticles dispersed in the insulator.
    Type: Application
    Filed: February 25, 2005
    Publication date: October 27, 2005
    Inventors: Mikihisa Mizuno, Yuichi Sasaki, Makoto Inoue, Kenji Yazawa, Migaku Takahashi, Yasuo Tateno, Teiichi Miyauchi
  • Publication number: 20050227122
    Abstract: A vertical magnetic recording medium exhibiting excellent noise characteristics in which magnetic interaction is reduced in a magnetic layer. The vertical magnetic recording medium (10) includes a nonmagnetic substrate (1), an underlying layer (2) formed directly or indirectly on the nonmagnetic substrate (1), and a magnetic layer (4) for recording magnetic information formed on the underlying layer (2), characterized in that the underlying layer (2) is composed of an alloy principally including two kinds of element, difference of standard free energy ?G° for producing an oxide or a nitride of the both elements at room temperature is set not lower than 70 kJ/mol[O2 or N2], and crystal grains constituting the underlying layer (2) principally includes one of two elements having a higher ?G°, and the grain boundary of the underlying layer (2) principally includes an oxide or a nitride of an element having a lower ?G°.
    Type: Application
    Filed: March 20, 2003
    Publication date: October 13, 2005
    Inventors: Migaku Takahashi, David Djayaprawira, Hirold Domon
  • Publication number: 20050214584
    Abstract: A method for producing a magnetic recording medium having a flat surface and a strong exchange bias field, and excellent in thermal stability. The method for producing a magnetic recording medium related to the present invention comprising a nonmagnetic substrate 1, a metal underlayer 2, and a ferromagnetic metal layer 3 formed successively in multilayer. The method comprises a step of forming the ferromagnetic layer 3 where ferromagnetic films 3a, 3b and one or more nonmagnetic metal spacer layer 4 are alternately formed in a multilayer and a step of allowing at least the interface of the nonmagnetic metal spacer layers 4 to physically adsorb oxygen and/or nitrogen.
    Type: Application
    Filed: March 20, 2003
    Publication date: September 29, 2005
    Inventors: Migaku Takahashi, David Djayaprawira, Hiroki Domon, Satoru Yoshimura
  • Publication number: 20050158585
    Abstract: A vertical magnetic recording medium has a low-noise characteristic compared to media of a permalloy or sendust crystalline material, including a high-flatness soft magnetic backing layer, and enabling recording/reproduction of information at high recording density, a magnetic recorder provided with the vertical magnetic recording medium, a vertical magnetic recording medium manufacturing method and apparatus. The vertical magnetic recording medium has a multilayer structure on a substrate, in which a soft magnetic backing layer, a vertical recording layer of a ferromagnetic body, and a protective layer are formed. The soft magnetic backing layer is formed of an FeSiAlN film of a soft magnetic material. The atom % of each element of Fe, Si, Al, and N of the FeSiAlN film can be changed by changing the flow rate of N2 gas in a mixture gas of N2 gas and Ar gas introduced into the chamber.
    Type: Application
    Filed: March 20, 2003
    Publication date: July 21, 2005
    Inventors: Migaku Takahashi, Shin Saito, David Djayaprawira
  • Publication number: 20050079551
    Abstract: An organic layer capable of forming surface areas having an adsorption property different from that of a periphery due to the chemical change of a surface functional group is formed on a board. The surface of the organic layer is patterned and oxidized by a scanning probe microscope to form an array pattern in which small sections for adsorbing nanoparticles are arranged. Then, nanoparticle dispersed solution is applied to the organic layer having the array pattern or the organic layer is dipped in the nanoparticle dispersed solution to form a particle layer on the organic layer. At this time, the nanoparticles in the nanoparticle dispersed solution are respectively fixed only onto the small sections. Therefore, a nanoparticle array on which groups of nanoparticles are arranged in an array can be obtained.
    Type: Application
    Filed: August 26, 2004
    Publication date: April 14, 2005
    Inventors: Mikihisa Mizuno, Yuichi Sasaki, Andrew Yu, Makoto Inoue, Migaku Takahashi, Kazuyuki Tohji, Jeyaderan Balachandran