Patents by Inventor Katsuhiko Koui

Katsuhiko Koui 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).

  • Spin torque oscillator and magnetic recording apparatus
    Patent number: 8467149
    Abstract: According to one embodiment, a spin torque oscillator includes a field generation layer, a spin injection layer including a first layer and a second layer, and an interlayer interposed between the field generation layer and the spin injection layer, wherein the first layer is interposed between the second layer and the interlayer and includes a (001)-oriented Heuslar magnetic alloy or a (001)-oriented magnetic material having a body-centered cubic lattice structure.
    Type: Grant
    Filed: August 25, 2011
    Date of Patent: June 18, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akihiko Takeo, Norihito Fujita, Mariko Kitazaki, Katsuhiko Koui, Hitoshi Iwasaki
  • Spin torque oscillator, magnetic recording head, magnetic head assembly and magnetic recording apparatus
    Patent number: 8467148
    Abstract: A spin torque oscillator includes an amorphous soft magnetic layer, a nonmagnetic layer and a hard magnetic layer. The nonmagnetic layer with a close-packed crystal structure is provided on the amorphous soft magnetic layer. The hard magnetic layer with a close-packed crystal structure and perpendicular magnetic anisotropy is provided on the nonmagnetic layer.
    Type: Grant
    Filed: October 6, 2009
    Date of Patent: June 18, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Soichi Oikawa, Katsuhiko Koui, Kenichiro Yamada
  • MAGNETIC RECORDING HEAD AND DISK DRIVE WITH THE SAME
    Publication number: 20130148242
    Abstract: According to one embodiment, a magnetic recording head includes a spin-torque oscillator between a main pole and a trailing shield. An oscillation layer of the spin-torque oscillator is formed by repeatedly stacking two or more laminates each including a metallic magnetic layer of a body-centered cubic crystalline metal and a metallic magnetic layer containing cobalt. The film thickness of each metallic magnetic layer is more than 0.2 nm and not more than 3 nm. The intensity of an anisotropic magnetic field is higher than a value obtained by subtracting the intensity of a gap magnetic field from the intensity of a diamagnetic field and lower than the intensity of the diamagnetic field.
    Type: Application
    Filed: August 14, 2012
    Publication date: June 13, 2013
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuhiko KOUI, Mariko KITAZAKI, Shuichi MURAKAMI, Kenichiro YAMADA
  • Magnetic recording device
    Patent number: 8446691
    Abstract: According to one embodiment, a magnetic recording device includes a magnetic recording head and a magnetic recording medium. The magnetic recording head includes a main magnetic pole, a shield and a stacked structure. The main magnetic pole has a medium facing surface and a main magnetic pole side surface. The shield has a shield side surface. The stacked structure is provided between the main magnetic pole and shield, and includes first and second magnetic layers, and an intermediate layer. The magnetic recording medium includes a backing layer and a magnetic recording layer. A distance between an end portion of the medium facing surface on a side of the stacked structure and the backing layer is twice or more of a distance between the main magnetic pole side surface and the shield side surface.
    Type: Grant
    Filed: April 30, 2012
    Date of Patent: May 21, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masayuki Takagishi, Hitoshi Iwasaki, Kenichiro Yamada, Katsuhiko Koui, Tomomi Funayama, Masahiro Takashita, Mariko Kitazaki, Soichi Oikawa
  • Spin injection layer robustness for microwave assisted magnetic recording
    Publication number: 20130082787
    Abstract: A spin transfer (torque) oscillator (STO) with a non-magnetic spacer formed between a spin injection layer (SIL) and a field generation layer (FGL), and with an interfacial layer comprised of Fe(100-V)CoV where v is from 5 to 100 atomic % formed between the SIL and non-magnetic spacer is disclosed. A composite seed layer made of Ta and a metal layer having a fcc(111) or hcp(001) texture is used to enhance perpendicular magnetic anisotropy (PMA) in the STO device. The interfacial layer quenches SIL oscillations and thereby stabilizes the SIL against FGL oscillations. The interfacial layer preferably has a thickness from 5 to 50 Angstroms and enhances amplitude (dR/R) in the STO device. The STO device may have a top SIL or bottom SIL configuration. The SIL is typically a laminated structure such as (Co/Ni)X where x is between 5 and 50.
    Type: Application
    Filed: October 3, 2011
    Publication date: April 4, 2013
    Inventors: Kunliang Zhang, Min Li, Yuchen Zhou, Soichi Oikawa, Hitoshi Iwasaki, Kenichiro Yamada, Katsuhiko Koui
  • MAGNETIC HEAD AND MAGNETIC RECORDING AND REPRODUCING DEVICE
    Publication number: 20130063840
    Abstract: According to one embodiment, a magnetic head has a main magnetic pole, a write-shield constituting the main magnetic pole and a magnetic circuit, and a spin torque oscillation element provided between the main magnetic pole and the write-shield. The spin torque oscillation element is provided with a first oscillation layer, a nonmagnetic spin sink layer, a second oscillation layer, a nonmagnetic intermediate layer, and a spin injection layer provided in sequence from the write-shield side to the main magnetic pole side. The nonmagnetic spin sink layer is formed of at least one element selected from the group consisting of Ru, Rh, Ta, W, Cr, Ir, Mo, Re, Nb, Pt, and Pd.
    Type: Application
    Filed: June 22, 2012
    Publication date: March 14, 2013
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Katsuhiko Koui, Shuichi Murakami, Mariko Kitazaki, Yusuke Tomoda, Norihito Fujita
  • MAGNETIC RECORDING HEAD AND DISK DRIVE PROVIDED THEREWITH
    Publication number: 20130050875
    Abstract: According to one embodiment, a magnetic recording head includes a main pole configured to apply a recording magnetic field to a recording layer of a recording medium, a trailing shield opposed to the main pole with a write gap therebetween, and a high-frequency oscillator between the main pole and the trailing shield in a range of a width of the main pole in a track width direction, and configured to generate a high-frequency magnetic field. The high-frequency oscillator includes a spin injection layer, an intermediate layer, and an oscillation layer, and at least the oscillation layer comprises divided oscillation regions.
    Type: Application
    Filed: August 2, 2012
    Publication date: February 28, 2013
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro YAMADA, Katsuhiko KOUI
  • Spin torque oscillator, magnetic recording head, magnetic head assembly and magnetic recording apparatus
    Patent number: 8325442
    Abstract: A spin torque oscillator includes a first magnetic layer, a second magnetic layer and a first nonmagnetic layer. The first magnetic layer includes a magnetic film of a magnetic material with a body-centered cubic (bcc) structure and an oriented {110} plane of the body-centered cubic structure, the oriented {110} plane being oriented substantially parallel to a principal plane of the magnetic film. The first nonmagnetic layer is disposed between the first magnetic layer and the second magnetic layer. In addition, a magnetic moment in the magnetic film precesses around an axis substantially parallel to the principal plane. Furthermore, a magnetic field is applied in a direction substantially perpendicular to the principal plane, and a current is passed perpendicularly to the principal plane.
    Type: Grant
    Filed: November 5, 2009
    Date of Patent: December 4, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsuhiko Koui, Mariko Shimizu, Kenichiro Yamada
  • Magnetic head assembly and magnetic recording/reproducing apparatus
    Patent number: 8320079
    Abstract: It is made possible to reduce the write magnetic field generated from the main magnetic pole toward the spin torque oscillator, so as to reduce the variation in the oscillation characteristics of the spin torque oscillator, and reduce the current required for oscillation. The magnetic head assembly includes: a recording magnetic pole; a spin torque oscillator that has first and second magnetic layers, and an intermediate layer interposed between the first and second magnetic layers, the spin torque oscillator generating a high-frequency magnetic field by applying a current between the first and second magnetic layers; and a third magnetic layer that is placed adjacent to at least part of a side face of the second magnetic layer.
    Type: Grant
    Filed: June 17, 2009
    Date of Patent: November 27, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Kenichiro Yamada, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Mariko Shimizu, Soichi Oikawa, Katsuhiko Koui
  • Perpendicular magnetic recording head provided with side shield and magnetic disk apparatus using the same
    Patent number: 8315015
    Abstract: According to one embodiment, a perpendicular magnetic recording head includes a main pole which generates a recording magnetic field, a return pole which forms a closed magnetic circuit for the recording magnetic field, and a side shield magnetically spaced from the main pole in a cross-track direction in which a point on a trailing edge of the side shield which is closest to the main pole is positioned on a leading side of a trailing edge of the main pole.
    Type: Grant
    Filed: March 27, 2012
    Date of Patent: November 20, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoko Taguchi, Tomomi Funayama, Yuka Aoyagi, Katsuhiko Koui
  • MAGNETIC RECORDING DEVICE
    Publication number: 20120275061
    Abstract: According to one embodiment, a magnetic recording device includes a magnetic recording head and a magnetic recording medium. The magnetic recording head includes a main magnetic pole, a shield and a stacked structure. The main magnetic pole has a medium facing surface and a main magnetic pole side surface. The shield has a shield side surface. The stacked structure is provided between the main magnetic pole and shield, and includes first and second magnetic layers, and an intermediate layer. The magnetic recording medium includes a backing layer and a magnetic recording layer. A distance between an end portion of the medium facing surface on a side of the stacked structure and the backing layer is twice or more of a distance between the main magnetic pole side surface and the shield side surface.
    Type: Application
    Filed: April 30, 2012
    Publication date: November 1, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masayuki TAKAGISHI, Hitoshi Iwasaki, Kenichiro Yamada, Katsuhiko Koui, Tomomi Funayama, Masahiro Takashita, Mariko Kitazaki, Soichi Oikawa
  • MAGNETIC RECORDING HEAD, HEAD GIMBAL ASSEMBLY WITH THE SAME, AND DISK DRIVE
    Publication number: 20120262821
    Abstract: According to one embodiment, a magnetic recording head includes a main pole configured to apply a recording magnetic field perpendicular to a recording medium, a trailing-shield pole opposed to the main pole with a recording gap therebetween, a high-frequency oscillator between the main pole and the trailing-shield pole in the recording gap, configured to produce a high-frequency magnetic field, a magnetic seed layer between the main pole and the high-frequency oscillator and in contact with the main pole, and a highly oriented magnetic layer of a soft magnetic material superposed on the magnetic seed layer between the main pole and the high-frequency oscillator and in contact with the high-frequency oscillator.
    Type: Application
    Filed: November 14, 2011
    Publication date: October 18, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoko Taguchi, Masayuki Takagishi, Katsuhiko Koui, Kenichiro Yamada, Hitoshi Iwasaki
  • MAGNETIC HEAD, HEAD GIMBAL ASSEMBLY WITH THE SAME, AND DISK DRIVE
    Publication number: 20120262820
    Abstract: According to one embodiment, a magnetic head includes a main pole configured to apply a recording magnetic field to a recording layer of a recording medium, a return pole opposed to the main pole with a write gap therebetween, and a high-frequency oscillator between respective facing surfaces of the main pole and the return pole and configured to produce a high-frequency magnetic field. At least one of the main and return poles faces the high-frequency oscillator and includes a laminated structure portion includes a magnetic layer and a nonmagnetic layer laminated to one another.
    Type: Application
    Filed: November 14, 2011
    Publication date: October 18, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takuya MATSUMOTO, Kenichiro YAMADA, Masayuki TAKAGISHI, Katsuhiko KOUI, Hitoshi IWASAKI
  • Magnetic recording head, magnetic head assembly, and magnetic recording apparatus
    Patent number: 8238058
    Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole, a shield, and a stacked structure body. The shield is provided to oppose the main magnetic pole. The stacked structure body is provided between the main magnetic pole and the shield. The stacked structure body includes a first magnetic layer, a second magnetic layer, and an intermediate layer. The first magnetic layer has coercivity lower than a magnetic field applied from the main magnetic pole. A size of a film surface of the second magnetic layer is larger than a size of a film surface of the first magnetic layer. The intermediate layer is provided between the first magnetic layer and the second magnetic layer and is made of a nonmagnetic material. A current is configured to pass between the first magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: February 7, 2011
    Date of Patent: August 7, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Mariko Shimizu, Hitoshi Iwasaki, Kenichiro Yamada, Katsuhiko Koui, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Soichi Oikawa
  • PERPENDICULAR MAGNETIC RECORDING HEAD AND MAGNETIC DISK APPARATUS
    Publication number: 20120182646
    Abstract: According to one embodiment, a perpendicular magnetic recording head includes a main pole which generates a recording magnetic field, a return pole which forms a closed magnetic circuit for the recording magnetic field, and a side shield magnetically spaced from the main pole in a cross-track direction in which a point on a trailing edge of the side shield which is closest to the main pole is positioned on a leading side of a trailing edge of the main pole.
    Type: Application
    Filed: March 27, 2012
    Publication date: July 19, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoko Taguchi, Tomomi Funayama, Yuka Aoyagi, Katsuhiko Koui
  • RECORDING HEAD, MAGNETIC HEAD ASSEMBLY, AND MAGNETIC RECORDING APPARATUS
    Publication number: 20120176702
    Abstract: A recording head including a first electrode, a first magnetic layer, a second magnetic layer, a first intermediate layer, a third magnetic layer, a second electrode, and a magnetic pole.
    Type: Application
    Filed: December 14, 2011
    Publication date: July 12, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro YAMADA, Hitoshi Iwasaki, Katsuhiko Koui
  • MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING/REPRODUCTION APPARATUS USING THE SAME
    Publication number: 20120170151
    Abstract: According to one embodiment, a recording track has a surface modification layer in the surface region. This surface modification layer has an anisotropic magnetic field Hk reduced from that of a region between adjacent recording tracks.
    Type: Application
    Filed: March 14, 2012
    Publication date: July 5, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Soichi OIKAWA, Hitoshi IWASAKI, Masayuki TAKAGISHI, Kenichiro YAMADA, Tomomi FUNAYAMA, Masahiro TAKASHITA, Katsuhiko KOUI, Mariko SHIMIZU
  • MAGNETIC RECORDER
    Publication number: 20120154952
    Abstract: A magnetic recorder includes: a magnetic recording medium; a reproducing head; a magnetic recording head including: a main magnetic pole; a first magnetic layer containing a TM alloy; a second magnetic layer containing a TM alloy or an RE-TM alloy; a third magnetic layer containing an RE-TM alloy; a first intermediate layer provided between the first magnetic layer and the second magnetic layer; and a second intermediate layer provided between the second magnetic layer and the third magnetic layer; and a signal processing portion which performs signal writing into the magnetic recording medium by using the magnetic recording head and reading from the magnetic recording medium by using the reproducing head.
    Type: Application
    Filed: February 24, 2012
    Publication date: June 21, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro YAMADA, Hitoshi IWASAKI, Masayuki TAKAGISHI, Tomomi FUNAYAMA, Masahiro TAKASHITA, Katsuhiko KOUI, Mariko KITAZAKI, Soichi OIKAWA
  • SPIN TORQUE OSCILLATOR, METHOD OF MANUFACTURING THE SAME, MAGNETIC RECORDING HEAD, MAGNETIC HEAD ASSEMBLY, AND MAGNETIC RECORDING APPARATUS
    Publication number: 20120140354
    Abstract: According to one embodiment, there is provided a spin torque oscillator including an oscillation layer formed of a magnetic material, a spin injection layer formed of a magnetic material and configured to inject a spin into the oscillation layer, and a current confinement layer including an insulating portion formed of an oxide or a nitride and a conductive portion formed of a nonmagnetic metal and penetrating the insulating portion in a direction of stacking. The conductive portion of the current confinement layer is positioned near a central portion of a plane of a device region including the oscillation layer and the spin injection layer.
    Type: Application
    Filed: November 8, 2011
    Publication date: June 7, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Akihiko TAKEO, Satoshi SHIROTORI, Kenichiro YAMADA, Katsuhiko KOUI
  • MAGNETIC RECORDING HEAD, MAGNETIC HEAD ASSEMBLY, AND MAGNETIC RECORDING APPARATUS
    Publication number: 20120134054
    Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole generating a recording magnetic field in a magnetic recording medium, a return yoke paired with the main magnetic pole and a spin torque oscillator interposed between the main magnetic pole and the return yoke and including a first magnetic layer, a second magnetic layer and a third magnetic layer of Fe4N, the second magnetic layer being interposed between the first magnetic layer and the third magnetic layer, wherein the magnetic recording head is configured to allow a current for oscillation to flow in a direction from the first magnetic layer to the third magnetic layer.
    Type: Application
    Filed: September 2, 2011
    Publication date: May 31, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Akihiko TAKEO, Mariko KITAZAKI, Kenichiro YAMADA, Katsuhiko KOUI, Hitoshi IWASAKI