Patents by Inventor Kenichiro Yamada

Kenichiro Yamada 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).

  • MAGNETIC RECORDING HEAD AND DISK DEVICE WITH THE SAME
    Publication number: 20150043106
    Abstract: According to one embodiment, a magnetic head includes a main pole configured to apply a recording magnetic field to a recording layer included in a recording medium, a trailing shield opposing the main pole in a down-track direction, with a write gap interposed therebetween, a pair of side shields opposing the main pole on opposite sides of the main pole in a cross-track direction, with respective gaps interposed therebetween, a recording coil configured to cause the main pole to generate a magnetic field, a first high-frequency oscillator interposed between the main pole and one of the side shields, and a second high-frequency oscillator interposed between the main pole and the other side shield.
    Type: Application
    Filed: October 25, 2013
    Publication date: February 12, 2015
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro YAMADA, Katsuhiko KOUI, Akihiko TAKEO
  • Spin torque oscillator, method of manufacturing the same, magnetic recording head, magnetic head assembly, and magnetic recording apparatus
    Patent number: 8929031
    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: Grant
    Filed: November 8, 2011
    Date of Patent: January 6, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akihiko Takeo, Satoshi Shirotori, Kenichiro Yamada, Katsuhiko Koui
  • MAGNETIC HEAD, MAGNETIC RECORDING REPRODUCING APPARATUS AND MAGNETIC HEAD MANUFACTURING METHOD
    Publication number: 20140376130
    Abstract: A magnetic head includes a plurality of reproducing elements so that the magnetic head can acquire reproduction signals from a plurality of tracks at the same time. The magnetic head includes a first reproducing element, a first magnetic film formed on a first side wall of the first reproducing element with a first side wall insulating film interposed therebetween, a second magnetic film formed on a second side wall of the first reproducing element with a second side wall insulating film interposed therebetween, a second reproducing element electrically isolated from the first reproducing element and formed on the first magnetic film, a third magnetic film formed on the first magnetic film, and a fourth magnetic film formed on the first reproducing element and electrically isolated from the second reproducing element.
    Type: Application
    Filed: January 10, 2014
    Publication date: December 25, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Akihiko TAKEO, Kazuto KASHIWAGI, Kenichiro YAMADA, Katsuhiko KOUI, Tomomi FUNAYAMA
  • MAGNETIC RECORDING HEAD AND DISK DRIVE WITH THE SAME
    Publication number: 20140362468
    Abstract: According to one embodiment, a magnetic recording head of a disk drive includes a main pole configured to produce a recording magnetic field perpendicular to a recording layer of a recording medium, a trailing shield located on the trailing side of the main pole with a write gap therebetween, a recording coil configured to produce a magnetic field in the main pole, and a nonmagnetic film containing a nonmagnetic material with a negative thermal expansion coefficient and disposed in the write gap between the trailing shield and a distal end portion of the main pole.
    Type: Application
    Filed: September 9, 2013
    Publication date: December 11, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Tomoko Taguchi, Kenichiro Yamada
  • Disk storage apparatus, write control apparatus and write control method
    Patent number: 8810954
    Abstract: According to one embodiment, a disk storage apparatus includes a magnetic head and a controller. The controller determines at regular intervals whether a recording density of a write signal belongs to a low-density region or a high-density region with reference to a reference density. In addition, the controller relatively reduces a current to energize a high-frequency-assisted element at a timing of the low-density region to be less than a current of the high-density region, in accordance with the low-density region or the high-density region in recording the data.
    Type: Grant
    Filed: September 11, 2013
    Date of Patent: August 19, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoko Taguchi, Kenichiro Yamada, Gaku Koizumi
  • MAGNETIC RECORDING HEAD, MAGNETIC HEAD ASSEMBLY, MAGNETIC RECORDING APPARATUS, AND MAGNETIC RECORDING METHOD
    Publication number: 20140198410
    Abstract: An example magnetic recording apparatus includes a magnetic recording medium and a magnetic recording head. The magnetic recording head includes a first magnetic pole to apply a recording magnetic field to a magnetic recording medium, a spin torque oscillator provided parallel to the first magnetic pole, a first coil which surrounds the first magnetic pole, to magnetize the first magnetic pole, and a second coil to pass a current independently of the first coil and magnetize the first magnetic pole. A signal processor writes and reads a signal on the magnetic recording medium by using the magnetic recording head.
    Type: Application
    Filed: February 19, 2014
    Publication date: July 17, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro YAMADA, Hitoshi IWASAKI, Masayuki TAKAGISHI
  • Magnetic recording head, magnetic head assembly, magnetic recording apparatus, and magnetic recording method
    Patent number: 8767346
    Abstract: A magnetic recording head includes a first magnetic pole, a second magnetic pole, a spin torque oscillator, a first coil, a second coil, and a third coil. The first magnetic pole applies a recording magnetic field to a magnetic recording medium. The second magnetic pole is provided parallel to the first magnetic pole. At least a portion of the spin torque oscillator is provided between the first magnetic pole and the second magnetic pole. The first coil magnetizes the first magnetic pole. A current is passed through the second coil independently of the first coil. A current is passed through the third coil independently of both the first coil and the second coil.
    Type: Grant
    Filed: November 30, 2009
    Date of Patent: July 1, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Masayuki Takagishi
  • MAGNETIC HEAD AND MAGNETIC RECORDING/REPRODUCTION APPARATUS
    Publication number: 20140177101
    Abstract: According to one embodiment, an oscillation layer of a spin torque oscillator for use in a magnetic head includes a stack of first and second metal films. The first metal film is formed by repetitively stacking a combination of first and second magnetic layers twice or more. The thickness of the first metal film is 0.4 to 5.0 nm. The first magnetic layer has a bcc structure and contains Fe. The second magnetic layer contains Co. The second metal film is made of Cu.
    Type: Application
    Filed: May 28, 2013
    Publication date: June 26, 2014
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Katsuhiko KOUI, Shuichi Murakami, Mariko Shimizu, Kenichiro Yamada
  • Magnetic head pole including laminated structure having magnetic and nonmagnetic layers
    Patent number: 8755147
    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: Grant
    Filed: September 5, 2013
    Date of Patent: June 17, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takuya Matsumoto, Kenichiro Yamada, Masayuki Takagishi, Katsuhiko Koui, Hitoshi Iwasaki
  • Magnetic recording head, head gimbal assembly with the same, and disk drive
    Patent number: 8730616
    Abstract: According to one embodiment, a magnetic recording head includes a main pole, a trailing shield opposing the main pole with a write gap therebetween, and a high-frequency oscillator between a distal end portion of the main pole and the trailing shield configured to produce a high-frequency magnetic field. The high-frequency oscillator includes a lower end surface facing the recording medium and an upper end surface substantially parallel to the lower end surface. The width of the lower end surface in a track-width direction is smaller than that of the upper end surface.
    Type: Grant
    Filed: August 14, 2012
    Date of Patent: May 20, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Yusuke Tomoda, Tomoko Taguchi, Katsuhiko Koui
  • Magnetic recording head and magnetic recording apparatus including the same
    Patent number: 8717705
    Abstract: According to one embodiment, a magnetic recording head includes a facing surface configured to face a recording medium, a main magnetic pole configured to apply a recording magnetic field to a recording layer of the recording medium, and a high-frequency oscillator disposed near to a trailing side of the main magnetic pole and configured to apply a high-frequency magnetic field to the recording layer. An angle defined between a recording magnetic field applied from the main magnetic pole to the recording medium and the facing surface is 0 to 85° in a region between a trailing side end of the main magnetic pole and a trailing side end of the high-frequency oscillator.
    Type: Grant
    Filed: May 17, 2013
    Date of Patent: May 6, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Naoyuki Narita, Katsuhiko Koui, Akihiko Takeo
  • Recording head with high-frequency oscillator and bi-layer main pole height/width arrangement
    Patent number: 8705204
    Abstract: According to one embodiment, a main pole of a recording head includes a first magnetic pole layer and a second magnetic pole layer laminated on the trailing side of the first magnetic pole layer. The first magnetic pole layer includes a tapered portion and a first tip portion. The second magnetic pole layer includes a tapered portion and a second tip portion. A width in a track direction of the second tip portion is smaller than that of the first tip portion. The high-frequency oscillator is between the second tip portion and the trailing shield and includes a width in the track direction substantially equal to the width in the track direction of the second tip portion, and a height of the first tip portion is taller than that of the second tip portion.
    Type: Grant
    Filed: August 21, 2012
    Date of Patent: April 22, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoko Taguchi, Kenichiro Yamada, Katsuhiko Koui, Tomomi Funayama, Norihito Fujita
  • Magnetic recording head and disk drive including the same
    Patent number: 8687322
    Abstract: According to one embodiment, a magnetic recording head of a disk drive includes a main pole configured to generate a magnetic field in a direction perpendicular to a recording layer of a recording medium, a write shield magnetic pole opposite to a trailing side of the main pole with a gap, a coil configured to excite a magnetic flux in a magnetic circuit, and a high-frequency oscillator provided between a tip portion of the main pole on a side of the recording medium and the write shield magnetic pole to generate a high-frequency magnetic field. The write shield magnetic pole includes an end face opposite to the high-frequency oscillator and the end face is formed so that a distance from the main pole increases with an increasing distance from the recording medium.
    Type: Grant
    Filed: March 11, 2013
    Date of Patent: April 1, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takuya Matsumoto, Tomoko Taguchi, Kenichiro Yamada, Naoyuki Narita
  • Magnetic head assembly
    Patent number: 8687321
    Abstract: A magnetic head assembly includes: a magnetic recording head, a head slider, a suspension and an actuator arm. The magnetic recording head includes a spin torque oscillator and a main magnetic pole. The spin torque oscillator includes, a first magnetic layer including at least one selected from the group consisting of a Fe—Co—Al alloy, a Fe—Co—Si alloy, a Fe—Co—Ge alloy, a Fe—Co—Mn alloy a Fe—Co—Cr alloy and a Fe—Co—B alloy, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. The main magnetic pole is placed together with the spin torque oscillator. The magnetic recording head is mounted on the head slider. The head slider is mounted on one end of the suspension. The actuator arm is connected to other end of the suspension.
    Type: Grant
    Filed: March 26, 2009
    Date of Patent: April 1, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Masayuki Takagishi, Tomomi Funayama
  • MAGNETIC RECORDING HEAD AND DISK DRIVE INCLUDING THE SAME
    Publication number: 20140078618
    Abstract: According to one embodiment, a magnetic recording head of a disk drive includes a main pole configured to generate a magnetic field in a direction perpendicular to a recording layer of a recording medium, a write shield magnetic pole opposite to a trailing side of the main pole with a gap, a coil configured to excite a magnetic flux in a magnetic circuit, and a high-frequency oscillator provided between a tip portion of the main pole on a side of the recording medium and the write shield magnetic pole to generate a high-frequency magnetic field. The write shield magnetic pole includes an end face opposite to the high-frequency oscillator and the end face is formed so that a distance from the main pole increases with an increasing distance from the recording medium.
    Type: Application
    Filed: March 11, 2013
    Publication date: March 20, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takuya Matsumoto, Tomoko Taguchi, Kenichiro Yamada, Naoyuki Narita
  • Magnetic recording head with high frequency oscillator and disk drive with the same
    Patent number: 8675308
    Abstract: According to one embodiment, a magnetic recording head includes a disk-facing surface configured to face a recording layer of a recording medium, a main magnetic pole includes a distal end located on the disk-facing surface and configured to apply a recording magnetic field to the recording layer of the recording medium, a leading shield on a leading side of the main magnetic pole, opposed to the distal end of the main magnetic pole across a gap, a high-frequency oscillator between the leading shield and the distal end of the main magnetic pole, and a recording coil configured to excite the main magnetic pole with a magnetic field.
    Type: Grant
    Filed: November 19, 2012
    Date of Patent: March 18, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Takuya Matsumoto, Naoyuki Narita, Tomoko Taguchi, Katsuhiko Koui, Akihiko Takeo
  • Magnetic head with spin torque oscillator and magnetic recording head
    Patent number: 8654480
    Abstract: An example magnetic head includes a recording pole to generate a recording magnetic field, a spin torque oscillator formed in the vicinity of the recording magnetic pole and a hard bias film provided at both end portions of a bias layer and an oscillation layer of spin torque oscillator. The hard bias film is configured to apply a magnetic field to the bias layer and the oscillation layer.
    Type: Grant
    Filed: July 10, 2012
    Date of Patent: February 18, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Mariko Shimizu, Hitoshi Iwasaki, Kenichiro Yamada, Junichi Akiyama, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita
  • MAGNETIC HEAD POLE INCLUDING LAMINATED STRUCTURE HAVING MAGNETIC AND NONMAGNETIC LAYERS
    Publication number: 20140002926
    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: September 5, 2013
    Publication date: January 2, 2014
    Inventors: Takuya MATSUMOTO, Kenichiro YAMADA, Masayuki TAKAGISHI, Katsuhiko KOUI, Hitoshi IWASAKI
  • MAGNETIC RECORDING HEAD, AND DISK DRIVE COMPRISING THE SAME
    Publication number: 20140002924
    Abstract: According to one embodiment, a magnetic recording head includes a disk-facing surface configured to face a recording layer of a recording medium, a main magnetic pole includes a distal end located on the disk-facing surface and configured to apply a recording magnetic field to the recording layer of the recording medium, a leading shield on a leading side of the main magnetic pole, opposed to the distal end of the main magnetic pole across a gap, a high-frequency oscillator between the leading shield and the distal end of the main magnetic pole, and a recording coil configured to excite the main magnetic pole with a magnetic field.
    Type: Application
    Filed: November 19, 2012
    Publication date: January 2, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro YAMADA, Takuya MATSUMOTO, Naoyuki NARITA, Tomoko TAGUCHI, Katsuhiko KOUI, Akihiko TAKEO
  • MAGNETIC RECORDING HEAD INCLUDING A HIGH-FREQUENCY OSCILLATOR AND DISK DRIVE WITH THE SAME
    Publication number: 20140002925
    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, and a high-frequency oscillator disposed adjacent to the main pole and near a air-bearing surface which faces the recording medium. The high-frequency oscillator includes a lower end surface located nearest to the air-bearing surface and an upper end surface located farthest from the air-bearing surface. A length of the lower end surface in a cross track direction is longer than a length of the upper end surface in the cross track direction.
    Type: Application
    Filed: December 12, 2012
    Publication date: January 2, 2014
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yusuke TOMODA, Kenichiro YAMADA, Naoyuki NARITA