Patents by Inventor Gohei Kurokawa

Gohei Kurokawa 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: 20220319546
    Abstract: A magnetic recording medium includes a magnesium oxide underlayer including magnesium oxide, and a magnetic layer including an alloy having a L10 structure and includes Fe or Co and Pt. The magnesium oxide has a peak of an O1s spectrum detected in a range of 531 eV to 533 eV when measured by X-ray photoelectron spectroscopy.
    Type: Application
    Filed: March 29, 2022
    Publication date: October 6, 2022
    Inventors: Chen XU, Gohei KUROKAWA, Lei ZHANG, Takayuki FUKUSHIMA, Tomoo SHIGE, Shin SAITO
  • Publication number: 20220050125
    Abstract: This probe production method is a method of producing a probe (101) having a coating layer (104) on a surface thereof, in which the coating layer (104) is formed on a surface of a base material (103) having a sharp tip end portion (103a) using a gas phase method.
    Type: Application
    Filed: March 3, 2020
    Publication date: February 17, 2022
    Applicant: SHOWA DENKO K.K.
    Inventors: Tsuyoshi KATO, Hiroyuki TOMITA, Takuya MINAMI, Shohei NISHIZAWA, Yoshitomo SHIMAZU, Gohei KUROKAWA, Katsumi MUROFUSHI, Naoya FUKUMOTO
  • Patent number: 10192571
    Abstract: A perpendicular magnetic recording medium includes a structure in which at least a soft magnetic backing layer, an underlayer, an intermediate layer, and a perpendicular magnetic recording layer are sequentially laminated on a non-magnetic substrate, in which the soft magnetic backing layer includes at least a soft magnetic film having an amorphous structure, the underlayer includes a first underlayer and a second underlayer laminated in this order from the non-magnetic substrate side, the first underlayer is made of a TiV alloy having an amorphous structure, the second underlayer includes a NiW alloy, the intermediate layer includes Ru or a Ru alloy, the soft magnetic film having an amorphous structure directly contacts the first underlayer, and the first underlayer directly contacts the second underlayer.
    Type: Grant
    Filed: April 12, 2016
    Date of Patent: January 29, 2019
    Assignee: SHOWA DENKO K.K.
    Inventors: Chen Xu, Gohei Kurokawa
  • Patent number: 10127932
    Abstract: A perpendicular magnetic recording medium includes a soft magnetic underlayer, an underlayer, an intermediate layer, and a perpendicular magnetic recording layer successively stacked on a nonmagnetic substrate. The soft magnetic underlayer includes a soft magnetic layer having an amorphous structure. The underlayer includes a first underlayer, and a second underlayer provided between the first underlayer and the intermediate layer. The first underlayer is made of a TiV alloy having an amorphous structure, and the second underlayer is made of an NiW alloy including at least one element selected from a group consisting of Co, Cu, Al, Cr, and Fe. The intermediate layer is made of Ru or an Ru alloy, and wherein the soft magnetic layer, the first underlayer, and the second underlayer are stacked in this order.
    Type: Grant
    Filed: April 1, 2016
    Date of Patent: November 13, 2018
    Assignee: SHOWA DENKO K.K.
    Inventors: Chen Xu, Gohei Kurokawa
  • Patent number: 10056103
    Abstract: A method of manufacturing a magnetic recording medium, includes at least: forming an orientation control layer 3 that controls orientation of an immediately above layer thereof on a non-magnetic substrate 1; and forming a perpendicular magnetic layer 4 in which an easy axis of magnetization is mainly perpendicularly orientated to the non-magnetic substrate 1, in which the forming of the orientation control layer 3 includes forming a granular layer having a granular structure that includes Ru or a material in which Ru is a main component and an oxide having a melting point which is greater than or equal to 450° C. and less than or equal to 1000° C., by a sputtering method, and the forming of the perpendicular magnetic layer 4 includes growing crystal grains to form columnar crystals that are continuous in a thickness direction together with crystal grains that form the orientation control layer 3.
    Type: Grant
    Filed: January 22, 2014
    Date of Patent: August 21, 2018
    Assignee: SHOWA DENKO K.K.
    Inventors: Ken Inoue, Gohei Kurokawa, Haruhisa Ohashi
  • Patent number: 9959895
    Abstract: A method for manufacturing a magnetic recording medium is provided. An orientation control layer is deposited on a non-magnetic substrate to control an orientation of a layer located directly thereon, and a perpendicular magnetic layer whose easy axis of magnetization is mainly oriented perpendicular to the non-magnetic substrate is deposited thereon. In depositing the orientation control layer, a first granular structure layer containing Ru or a material mainly made of Ru and a first oxide having a melting point of 1000 degrees C. or lower are deposited by sputtering. In depositing the perpendicular magnetic layer, a second granular structure layer containing magnetic particles and a second oxide having a melting point of 1000 degrees C. or lower are deposited by sputtering, and the magnetic particles are grown so as to form a columnar crystal continuing in a thickness direction. The columnar crystal includes crystal grains constituting the orientation control layer.
    Type: Grant
    Filed: July 30, 2014
    Date of Patent: May 1, 2018
    Assignee: SHOWA DENKO K.K.
    Inventors: Ken Inoue, Kenji Shimizu, Gohei Kurokawa, Haruhisa Ohashi
  • Publication number: 20160351223
    Abstract: A perpendicular magnetic recording medium includes a soft magnetic underlayer, an underlayer, an intermediate layer, and a perpendicular magnetic recording layer successively stacked on a nonmagnetic substrate. The soft magnetic underlayer includes a soft magnetic layer having an amorphous structure. The underlayer includes a first underlayer, and a second underlayer provided between the first underlayer and the intermediate layer. The first underlayer is made of a TiV alloy having an amorphous structure, and the second underlayer is made of an NiW alloy including at least one element selected from a group consisting of Co, Cu, Al, Cr, and Fe. The intermediate layer is made of Ru or an Ru alloy, and wherein the soft magnetic layer, the first underlayer, and the second underlayer are stacked in this order.
    Type: Application
    Filed: April 1, 2016
    Publication date: December 1, 2016
    Inventors: Chen XU, Gohei KUROKAWA
  • Publication number: 20160300591
    Abstract: A perpendicular magnetic recording medium includes a structure in which at least a soft magnetic backing layer, an underlayer, an intermediate layer, and a perpendicular magnetic recording layer are sequentially laminated on a non-magnetic substrate, in which the soft magnetic backing layer includes at least a soft magnetic film having an amorphous structure, the underlayer includes a first underlayer and a second underlayer laminated in this order from the non-magnetic substrate side, the first underlayer is made of a TiV alloy having an amorphous structure, the second underlayer includes a NiW alloy, the intermediate layer includes Ru or a Ru alloy, the soft magnetic film having an amorphous structure directly contacts the first underlayer, and the first underlayer directly contacts the second underlayer.
    Type: Application
    Filed: April 12, 2016
    Publication date: October 13, 2016
    Applicant: SHOWA DENKO K.K.
    Inventors: Chen XU, Gohei KUROKAWA
  • Patent number: 9129636
    Abstract: The present invention provides a method for manufacturing a magnetic recording medium by mounting a substrate for film formation on a carrier, sequentially transporting said substrate into a plurality of connected chambers, and forming at least a magnetic film and a carbon protective film on said substrate for film formation within said chambers, wherein said method comprises a step of conducting ashing to remove an accumulated carbon protective film adhered to a carrier surface, which is performed following a step of removing a magnetic recording medium from said carrier following film formation, but prior to a step of mounting a substrate for film formation on said carrier.
    Type: Grant
    Filed: July 3, 2008
    Date of Patent: September 8, 2015
    Assignee: SHOWA DENKO K.K.
    Inventor: Gohei Kurokawa
  • Patent number: 8968526
    Abstract: There are provided a method for manufacturing a magnetic recording medium which is excellent in terms of both the recording and reproduction characteristics and the thermal fluctuation characteristics without reducing the density and hardness of the perpendicular magnetic layer; a magnetic recording medium; and a magnetic recording and reproducing apparatus with which an excellent recording density is achieved, wherein, in the method for manufacturing the magnetic recording medium, at least a portion of the perpendicular magnetic layer 4 is formed as a magnetic layer having a granular structure that contains Co as a major component and also contains an oxide of at least one nonmagnetic metal selected from the group consisting of Cr, Si, Ta, Al, Ti, W and Mg; a target for forming the perpendicular magnetic layer 4 by the sputtering process is prepared so as to include an oxide of Co and a compound of Co and at least one nonmagnetic metal selected from the group consisting of Cr, Si, Ta, Al, Ti, W and Mg, an
    Type: Grant
    Filed: January 22, 2010
    Date of Patent: March 3, 2015
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba, Tohoku University
    Inventors: Shingo Sasaki, Shin Saito, Migaku Takahashi, Atsushi Hashimoto, Yuzo Sasaki, Gohei Kurokawa, Tomoyuki Maeda, Akihiko Takeo
  • Publication number: 20150036243
    Abstract: A method for manufacturing a magnetic recording medium is provided. An orientation control layer is deposited on a non-magnetic substrate to control an orientation of a layer located directly thereon, and a perpendicular magnetic layer whose easy axis of magnetization is mainly oriented perpendicular to the non-magnetic substrate is deposited thereon. In depositing the orientation control layer, a first granular structure layer containing Ru or a material mainly made of Ru and a first oxide having a melting point of 1000 degrees C. or lower are deposited by sputtering. In depositing the perpendicular magnetic layer, a second granular structure layer containing magnetic particles and a second oxide having a melting point of 1000 degrees C. or lower are deposited by sputtering, and the magnetic particles are grown so as to form a columnar crystal continuing in a thickness direction. The columnar crystal includes crystal grains constituting the orientation control layer.
    Type: Application
    Filed: July 30, 2014
    Publication date: February 5, 2015
    Inventors: Ken INOUE, Kenji SHIMIZU, Gohei KUROKAWA, Haruhisa OHASHI
  • Patent number: 8837087
    Abstract: According to one embodiment, there is provided a thin magnetic film having a negative anisotropy of ?6×106 erg/cm3 or less and including, on at least a nonmagnetic substrate, at least one seed layer made of a metal or metal compound, a ruthenium underlayer for controlling the orientation of an immediately overlying layer, and a magnetic layer having negative anisotropy in the normal line direction perpendicular to a surface of the magnetic layer and mainly containing Co and Ir, wherein the additive element concentration of Ir in the magnetic layer is 10 (inclusive) to 45 (inclusive) at %.
    Type: Grant
    Filed: July 19, 2013
    Date of Patent: September 16, 2014
    Assignees: Kabushiki Kaisha Toshiba, Tohoku University, Showa Denko K.K.
    Inventors: Akihiko Takeo, Akira Kikitsu, Tomoyuki Maeda, Migaku Takahashi, Shin Saito, Ken Inoue, Gohei Kurokawa
  • Publication number: 20140204484
    Abstract: A method of manufacturing a magnetic recording medium, includes at least: forming an orientation control layer 3 that controls orientation of an immediately above layer thereof on a non-magnetic substrate 1; and forming a perpendicular magnetic layer 4 in which an easy axis of magnetization is mainly perpendicularly orientated to the non-magnetic substrate 1, in which the forming of the orientation control layer 3 includes forming a granular layer having a granular structure that includes Ru or a material in which Ru is a main component and an oxide having a melting point which is greater than or equal to 450° C. and less than or equal to 1000° C., by a sputtering method, and the forming of the perpendicular magnetic layer 4 includes growing crystal grains to form columnar crystals that are continuous in a thickness direction together with crystal grains that form the orientation control layer 3.
    Type: Application
    Filed: January 22, 2014
    Publication date: July 24, 2014
    Applicant: SHOWA DENKO K.K.
    Inventors: Ken INOUE, Gohei KUROKAWA, Haruhisa OHASHI
  • Publication number: 20140139952
    Abstract: According to one embodiment, there is provided a thin magnetic film having a negative anisotropy of ?6×106 erg/cm3 or less and including, on at least a nonmagnetic substrate, at least one seed layer made of a metal or metal compound, a ruthenium underlayer for controlling the orientation of an immediately overlying layer, and a magnetic layer having negative anisotropy in the normal line direction perpendicular to a surface of the magnetic layer and mainly containing Co and Ir, wherein the additive element concentration of Ir in the magnetic layer is 10 (inclusive) to 45 (inclusive) at %.
    Type: Application
    Filed: July 19, 2013
    Publication date: May 22, 2014
    Inventors: Akihiko Takeo, Akira Kikitsu, Tomoyuki Maeda, Migaku Takahashi, Shin Saito, Ken Inoue, Gohei Kurokawa
  • Publication number: 20140104997
    Abstract: A magnetic recording medium is disclosed in which, on a non-magnetic substrate 1, at least an orientation control layer that controls orientation of a layer immediately above and a vertical magnetic layer in which an easy axis of magnetization is mainly vertically oriented with respect to the non-magnetic substrate are laminated. The orientation control layer includes an Ru-containing layer containing Ru or Ru alloy, and a diffusion prevention layer provided on the Ru-containing layer on the side of the vertical magnetic layer, is made of a material having a melting point of 1500° C. or higher and 4215° C. or lower and formed by a covalent bond or an ionic bond, and prevents thermal diffusion of Ru atoms of the Ru-containing layer.
    Type: Application
    Filed: October 10, 2013
    Publication date: April 17, 2014
    Applicants: SHOWA DENKO K.K., TOHOKU UNIVERSITY, KABUSHIKI KAISHA TOSHIBA
    Inventors: Hisato SHIBATA, Ken INOUE, Tsubasa OKADA, Gohei KUROKAWA, Shin SAITO, Shintaro HINATA, Migaku TAKAHASHI, Tomoyuki MAEDA, Yosuke ISOWAKI, Akira KIKITSU
  • Patent number: 8529989
    Abstract: The present invention relates to a method for manufacturing a perpendicular magnetic recording medium including a nonmagnetic substrate, and at least a soft magnetic under layer, an orientation control layer, a magnetic recording layer constituted of two or more layers and a protective layer formed on the nonmagnetic substrate, the method including a step of forming a first magnetic recording layer having a granular structure constituted of ferromagnetic crystal grains and crystal grain boundaries made of a nonmagnetic oxide or nitride on the nonmagnetic substrate side, a step of forming a second magnetic recording layer constituted only of ferromagnetic crystal grains, a step of forming a surface unevenness control layer for decreasing surface unevenness of the first magnetic recording layer located between the first magnetic recording layer and the second magnetic recording layer, and a step of heating the nonmagnetic substrate so as to decrease a surface roughness Ra of the second magnetic recording layer
    Type: Grant
    Filed: October 2, 2008
    Date of Patent: September 10, 2013
    Assignee: Showa Denko K.K.
    Inventors: Gohei Kurokawa, Yuzo Sasaki
  • Patent number: 8512884
    Abstract: A perpendicular magnetic recording medium including at least a soft under layer, an orientation control layer, a magnetic recording layer and a protective layer on a non-magnetic substrate, wherein the orientation control layer is composed of three or more layers including a seed layer, a first intermediate layer and a second intermediate layer sequentially, formed in that order from the substrate side, the crystal grains that constitute the first intermediate layer are epitaxially grown on the crystal grains of the seed layer, the crystal grains that constitute the second intermediate layer are epitaxially grown on the crystal grains of the first intermediate layer, and the crystal grains that constitute the second intermediate layer are finer than the crystal grains that constitute the first intermediate layer.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: August 20, 2013
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba, Tohoku University
    Inventors: Migaku Takahashi, Shin Saito, Gohei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Atsushi Hashimoto, Akihiko Takeo, Tomoyuki Maeda
  • Patent number: 8367155
    Abstract: There is provided a manufacturing method of a magnetic recording medium that maintains a high level of perpendicular orientation of a perpendicular magnetic layer and enables to further increase high recording density, prepared such that at least on a non-magnetic substrate, there are laminated a soft magnetic base layer, an orientation control layer 11 that controls the orientation of the layer immediately thereabove, and a perpendicular magnetic layer with a magnetization easy axis thereof primarily oriented perpendicular to the non-magnetic substrate.
    Type: Grant
    Filed: January 26, 2010
    Date of Patent: February 5, 2013
    Assignee: Showa Denko K.K.
    Inventors: Atsushi Hashimoto, Yuzo Sasaki, Gohei Kurokawa
  • Patent number: 8133601
    Abstract: A magnetic recording medium is provided which can record and reproduce high-density information by maintaining perpendicular orientation of a magnetic recording layer even with a decrease in thickness of nonmagnetic layers from an intermediate layer to a seed layer while decreasing the grain size of magnetic crystal grains to be consistent with an increase in recording density. A manufacturing method thereof and a magnetic recording and reproducing apparatus are also provided. The magnetic recording medium is a perpendicular magnetic recording medium including at least an underlying layer, an orientation control layer, a magnetic recording layer, and a protective layer formed on a nonmagnetic substrate. Here, the orientation control layer includes two or more layers of a seed layer and an intermediate layer from the substrate side.
    Type: Grant
    Filed: August 25, 2008
    Date of Patent: March 13, 2012
    Assignee: Showa Denko K.K.
    Inventors: Gohei Kurokawa, Yuzo Sasaki, Tatsu Komatsuda, Atsushi Hashimoto
  • Publication number: 20110293966
    Abstract: A magnetic recording medium which has been made by forming at least one magnetic layer having a granular structure on a substrate by sputtering, wherein said at least one magnetic recording layer having a granular structure comprises magnetic grains separated from each other by an oxide, and is made by sputtering a target comprising cobalt oxide and substantially free from metallic chromium and a chromium alloy. The magnetic grains in the granular structure have an average grain diameter of not larger than 6 nm, and are separated from each other by the oxide with a grain boundary width of at least 1.5 nm. The magnetic grains are minute and separated from each other with an enhanced grain boundary width, and the magnetic recording medium exhibits an enhanced recording density and improved electromagnetic conversion characteristics.
    Type: Application
    Filed: May 25, 2011
    Publication date: December 1, 2011
    Applicant: SHOWA DENKO K.K.
    Inventors: Atsushi HASHIMOTO, Takayuki Fukushima, Gohei Kurokawa