Patents by Inventor Akira Kikitsu

Akira Kikitsu 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: 20100006537
    Abstract: According to one embodiment, a method of manufacturing a magnetic recording medium includes depositing a magnetic recording layer on a substrate, the magnetic recording layer having a multi-layered structure of two or more layers at least one layer of which has a granular structure including CoCrPt alloy and SiO2, TiO2, CrO2, CoO2 or Ta2O5, forming masks on areas corresponding to recording regions of the magnetic recording layer, partially etching the magnetic recording layer in areas not covered with the masks with an etching gas to expose the granular layer of the magnetic recording layer and to form protrusions and recesses on the magnetic recording layer, modifying the granular layer of the magnetic recording layer remaining in the recesses with modifying gas, promoting modification reaction to form non-recording regions, and forming a protective film on an entire surface.
    Type: Application
    Filed: September 16, 2009
    Publication date: January 14, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshiyuki KAMATA, Akira KIKITSU, Yosuke ISOWAKI, Kaori KIMURA, Satoshi SHIROTORI, Masatoshi SAKURAI
  • Patent number: 7635529
    Abstract: According to one embodiment, a substrate for a magnetic recording media has circumferential protrusions corresponding to recording tracks and circumferential recesses corresponding to grooves between the recording tracks, in which the substrate satisfying at least one of conditions of (a) a surface of the recess has a surface energy smaller than that of the protrusion, (b) the surface of the recess is modified with a thermally decomposable or deformable substance, (c) the surface of the recess has surface roughness smaller than that of the protrusion, (d) crystal orientation is more disturbed on the surface of the recess than on the protrusion, (e) the surface of the recess is modified with a substance that causes reaction with a magnetic material or that diffuses into the magnetic material, and (f) the surface of the recess is modified with a substance soluble in a solvent or with a deformable substance.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: December 22, 2009
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Katsuyuki Naito, Masatoshi Sakurai, Akira Kikitsu, Yoshiyuki Kamata, Naoko Kihara, Masahiro Oka
  • Patent number: 7625645
    Abstract: According to one embodiment, a patterned magnetic recording media has a magnetic recording layer and a protective layer formed on a substrate, in which the magnetic recording layer including a magnetic material patterned in tracks and a nonmagnetic material filled in between the tracks in a data area, and has a recessed portion formed in an area within 1 mm from an outer media end and extending to the media end. The recessed portion being formed 1 to 50 nm deeper than the data area.
    Type: Grant
    Filed: January 30, 2006
    Date of Patent: December 1, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akira Kikitsu, Yoshiyuki Kamata, Takayuki Yamamoto, Hiroyuki Hyodo
  • Patent number: 7622204
    Abstract: A large grain diameter under-layer of at least one selected from Cu, Ni or Rh, comprising large average diameter crystalline grains of 50 nm or more than 50 nm with the (100) crystal plane of the grains oriented parallel to the substrate surface, was formed on a substrate. Then, a magnetic recording layer was deposited on the under-layer. The magnetic recording medium carrying this structure showed very small magnetic crystalline grains in magnetic layer, and excellent overwrite characteristics and signal to noise ratio at high recording density.
    Type: Grant
    Filed: March 9, 2005
    Date of Patent: November 24, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoyuki Maeda, Akira Kikitsu, Soichi Oikawa, Takeshi Iwasaki
  • Patent number: 7618549
    Abstract: According to one embodiment, a method of forming patterns is provided, in which the method including forming a resist on an underlying material, pressing a stamper having patterns of protrusions and recesses, sidewalls of which protrusions are tapered, onto the resist to form a patterned resist having patterns of protrusions and recesses, sidewalls of which protrusions are tapered, forming a protective film on the patterned resist, performing anisotropic etching to leave the protective film on the tapered sidewalls of protrusions of the patterned resist, etching a resist residue remaining in recesses of the patterned resist using the protective film as a mask, and etching the underlying material using the protective film and the patterned resist as a mask.
    Type: Grant
    Filed: October 16, 2006
    Date of Patent: November 17, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Satoshi Shirotori, Yoshiyuki Kamata, Masatoshi Sakurai, Akira Kikitsu
  • Publication number: 20090273858
    Abstract: It is possible to improve the recording and reproducing S/N ratio, the reproduction signal intensity, and the degree of high density recording. There are provided a plurality of recording tracks formed on a substrate, each recording track being formed of a magnetic material, and non-recording sections formed on the substrate, each non-recording section separating adjacent recording tracks, each recording track including a plurality of recording sections and connecting sections for connecting the recording sections adjacent thereto in a track longitudinal direction, and each connecting section having a cross-sectional area in a track width direction that is smaller than a cross-sectional area in a track width direction of adjacent recording sections.
    Type: Application
    Filed: July 15, 2009
    Publication date: November 5, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kaori KIMURA, Masatoshi Sakurai, Akira Kikitsu, Yoshiyuki Kamata, Satoshi Shirotori, Hiroyuki Hieda
  • Publication number: 20090231755
    Abstract: The invention provides a magnetic recording medium, and a magnetic recording and reproducing apparatus. The magnetic recording medium includes a substrate 11, an under layer 12 formed on the substrate 11, a magnetic recording layer 13 formed on the under layer 12, and a protective layer 14 formed on the magnetic recording layer 13. The magnetic recording layer 13 is composed of a primary recording layer 14 and a secondary recording layer 15 which are mutually exchange-coupled. The primary recording layer 14 has magnetic grains and a nonmagnetic material that surrounds the magnetic grains, and has a perpendicular magnetic anisotropy. The secondary recording layer 15 is made of a material having a negative crystal magnetic anisotropy and its easy plane of the magnetization is a plane of the medium.
    Type: Application
    Filed: June 9, 2006
    Publication date: September 17, 2009
    Inventors: Migaku Takahashi, Masahiro Oka, Akira Kikitsu
  • Patent number: 7580223
    Abstract: According to one embodiment, a magnetic recording media includes a substrate having recording tracks and separating regions separating the recording tracks, the separating regions having patterns of protrusions and recesses formed therein, and a recording film deposited on the substrate, in which a difference in height between a top of the recording track and a top of the separating region is 2 nm or more and 7 nm or less, and a difference in height between the top of the recording track and a bottom of the separating region is 10 nm or more.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: August 25, 2009
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Masatoshi Sakurai, Akira Kikitsu, Masahiro Oka
  • Publication number: 20090195925
    Abstract: According to one embodiment, a patterned magnetic recording media has a magnetic recording layer and a protective layer formed on a substrate, in which the magnetic recording layer including a magnetic material patterned in tracks and a nonmagnetic material filled in between the tracks in a data area, and has a recessed portion formed in an area within 1 mm from an outer media end and extending to the media end. The recessed portion being formed 1 to 50 nm deeper than the data area.
    Type: Application
    Filed: April 6, 2009
    Publication date: August 6, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Akira Kikitsu, Yoshiyuki Kamata, Takayuki Yamamoto, Hiroyuki Hyodo
  • Publication number: 20090135519
    Abstract: A magnetic recording medium includes a disk substrate, and recording cells arrayed on the disk substrate in a track direction, the recording cells includes a ferromagnetic pattern and a magnetic pattern formed on one of two sidewalls of the ferromagnetic pattern in the track direction and having a lower crystalline magnetic anisotropy constant Ku than that of the ferromagnetic pattern.
    Type: Application
    Filed: November 20, 2008
    Publication date: May 28, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hiroyuki Hieda, Kazuto Kashiwagi, Akira Kikitsu, Yousuke Isowaki, Yoshiyuki Kamata
  • Patent number: 7494725
    Abstract: A grain diameter controlling crystalline layer comprising crystalline grains of a metal selected from the group consisting essentially of Cu, Ni, Rh and Pt was formed on a substrate. Then, deposited atom layer of at least one element selected from the group consisting of oxygen and carbon was formed on the surface of the grain diameter control layer. A magnetic recording layer was deposited on the atoms deposited grain diameter controlling crystalline layer. Then a magnetic recording medium in which the magnetic crystalline grains has small grain diameter and small grain diameter distribution, and the magnetic recording medium shows increased signal to noise ratio at high recording density.
    Type: Grant
    Filed: March 22, 2005
    Date of Patent: February 24, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoyuki Maeda, Akira Kikitsu, Soichi Oikawa, Takeshi Iwasaki
  • 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: 20090015958
    Abstract: A magnetic recording device includes: a laminated body including: a first ferromagnetic layer with a magnetization substantially fixed in a first direction; a second ferromagnetic layer with a variable magnetization direction; a first nonmagnetic layer disposed between the first ferromagnetic layer and the second ferromagnetic layer; and a third ferromagnetic layer with a variable magnetization direction. The magnetization direction of the second ferromagnetic layer is determinable in response to the orientation of a current, by allowing electrons spin-polarized by passing a current in a direction generally perpendicular to the film plane of the layers of the laminated body to act on the second ferromagnetic layer, and by allowing a magnetic field generated by precession of the magnetization of the third ferromagnetic layer to act on the second ferromagnetic layer.
    Type: Application
    Filed: July 11, 2008
    Publication date: January 15, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Shiho Nakamura, Hirofumi Morise, Satoshi Yanagi, Daisuke Saida, Akira Kikitsu
  • Patent number: 7443626
    Abstract: A patterned disk medium includes a disk-shaped flat substrate including a first surface and a second surface located an opposite side of the first surface. First servo pattern areas including portions provided with magnetic members and portions provided with no magnetic members are provided on the first surface. Second servo pattern areas including portions provided with magnetic members and portions provided with no magnetic members are provided on the second surface. The magnetic members of the first and second servo pattern areas are magnetized in a direction perpendicular to the first and second surfaces. The magnetic polarity of the surfaces of the magnetic members of the second pattern areas differs from that of the surfaces of the magnetic members of the first pattern areas.
    Type: Grant
    Filed: July 15, 2005
    Date of Patent: October 28, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Makoto Asakura, Yoichiro Tanaka, Akira Kikitsu
  • Publication number: 20080260942
    Abstract: A grain diameter controlling crystalline layer comprising crystalline grains of a metal selected from the group consisting essentially of Cu, Ni, Rh and Pt was formed on a substrate. Then, deposited atom layer of at least one element selected from the group consisting of oxygen and carbon was formed on the surface of the grain diameter control layer. A magnetic recording layer was deposited on the atoms deposited grain diameter controlling crystalline layer. Then a magnetic recording medium in which the magnetic crystalline grains has small grain diameter and small grain diameter distribution, and the magnetic recording medium shows increased signal to noise ratio at high recording density.
    Type: Application
    Filed: October 19, 2007
    Publication date: October 23, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoyuki MAEDA, Akira KIKITSU, Soichi OIKAWA, Takeshi IWASAKI
  • Patent number: 7431999
    Abstract: Disclosed is a perpendicular magnetic recording medium including: a nonmagnetic substrate; a first underlayer formed on the nonmagnetic substrate, mainly composed of at least two kinds selected from a group consisting of Fe2O3, Co3O4, MgO, MoO3, Mn3O4, SiO2, Al2O3, TiO2, and ZrO2, and having crystal grains growing in a columnar shape and crystal grain boundaries surrounding the crystal grains; a nonmagnetic second underlayer formed on the first underlayer and having crystal grains with one of a face-centered cubic structure and a hexagonal close-packed structure growing on the crystal grains of the first underlayer; a magnetic layer formed on the second underlayer; and a protective film formed on the magnetic layer.
    Type: Grant
    Filed: March 17, 2005
    Date of Patent: October 7, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Iwasaki, Akira Kikitsu, Soichi Oikawa, Tomoyuki Maeda
  • Patent number: 7416794
    Abstract: A magnetic recording layer is formed on an under-layer comprising a Cu crystalline grain layer and a deposited nitrogen atom layer on the Cu crystalline grain layer surface. Then the magnetic recording layer comprising very small average grain diameter and sharp grain diameter distribution is obtained. The magnetic recording medium comprising the magnetic recording layer shows excellent signal to noise ratio at high density recording.
    Type: Grant
    Filed: March 16, 2005
    Date of Patent: August 26, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoyuki Maeda, Akira Kikitsu, Soichi Oikawa, Takeshi Iwasaki
  • 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
  • Patent number: 7372648
    Abstract: A pair of members opposed to each other via a gap are commonly used as an evanescent light probe and a writing magnetic head. When the spacing and width of the gap are smaller than the wavelength ? of injected light, highly intensive evanescent light is generated from the gap position of the opposite surface. Magnetic writing is carried out by applying a recording magnetic field from the pair of members to a medium heated by the evanescent light.
    Type: Grant
    Filed: August 18, 2004
    Date of Patent: May 13, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Junichi Akiyama, Akira Kikitsu, Tadashi Kai, Toshihiko Nagase, Tomoyuki Maeda
  • Publication number: 20080096050
    Abstract: A magnetic recording medium capable of alleviating thermal fluctuation and improving the recording density includes a functional layer containing a magnetic material, and a recording layer overlying the functional layer and containing a magnetic material. The recording layer contains a plurality of magnetic grains and a nonmagnetic material existing among the magnetic grains, and the functional layer and the recording layer exert exchange coupling interaction in a direction making a substantially orthogonal relation with each other at room temperature.
    Type: Application
    Filed: December 11, 2007
    Publication date: April 24, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Akira KIKITSU, Tadashi Kai, Junichi Akiyama