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).

  • Patent number: 8614861
    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: Grant
    Filed: December 12, 2012
    Date of Patent: December 24, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yusuke Tomoda, Kenichiro Yamada, Naoyuki Narita
  • Publication number: 20130329317
    Abstract: An example magnetic writing head includes a main magnetic pole and a coil to generate an ampere magnetic field to magnetize the main magnetic pole to cause the magnetized main magnetic pole to generate a magnetic field. The laminated body includes a first magnetic layer, and a second magnetic layer.
    Type: Application
    Filed: August 13, 2013
    Publication date: December 12, 2013
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro YAMADA, Hitoshi IWASAKI, Junichi AKIYAMA, Masayuki TAKAGISHI, Tomomi FUNAYAMA, Masahiro TAKASHITA, Mariko SHIMIZU, Shuichi MURAKAMI, Tadashi KAI
  • Publication number: 20130314818
    Abstract: A recording head includes a main magnetic pole generating a recording magnetic field in a direction perpendicular to a recording medium, a write shield magnetic pole facing a trailing side of the main magnetic pole, a recording coil exciting a magnetic flux in a magnetic circuit, and a spin torque oscillator provided between the main magnetic pole and the write shield magnetic pole. The main magnetic pole includes a trailing side end surface that faces the spin torque oscillator and is tilted toward a leading side of the recording head with respect to the direction perpendicular to the recording medium, and the spin torque oscillator has layers with tilted surfaces that are substantially in parallel with the trailing side end surface.
    Type: Application
    Filed: October 24, 2012
    Publication date: November 28, 2013
    Inventors: Takuya Maatsumoto, Kenichiro Yamada, Noayuki Narita
  • Patent number: 8564904
    Abstract: According to one embodiment, a magnetic head includes a reproducing section. The reproducing section detects a medium magnetic field recorded in a magnetic recording medium. The reproducing section includes a stacked film and a magnetic field application unit. The stacked film includes a first magnetization layer and a second magnetization layer. The first magnetization layer has a perpendicular magnetic anisotropy. A magnetization of the first magnetization layer being is fixed. The second magnetization layer is stacked with the first magnetization layer and oscillates. The magnetic field application unit is stacked with the stacked film and applies a bias magnetic field having a component along the first axis to the stacked film. A resistance of the stacked film changes in accordance with the medium magnetic field when a current not less than a value at which the second magnetization layer oscillates is passed.
    Type: Grant
    Filed: September 22, 2011
    Date of Patent: October 22, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Masayuki Takagishi, Kenichiro Yamada, Susumu Hashimoto, Yusuke Tomoda
  • Patent number: 8559134
    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. A product of saturated magnetization of the first magnetic layer and a lateral area of the first magnetic layer is larger than a product of saturated magnetization of the third magnetic layer and a lateral area of the third magnetic layer.
    Type: Grant
    Filed: December 14, 2011
    Date of Patent: October 15, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Katsuhiko Koui
  • Patent number: 8553359
    Abstract: A magnetic recording head includes a magnetic pole, a spin torque oscillator, a first shield and a second shield. The magnetic pole has an air-bearing surface. The spin torque oscillator is provided so that a first side of the spin torque oscillator faces the magnetic pole in a first direction parallel to the air-bearing surface. The first shield includes a granular magnetic material, and is provided so that two portions of the first shield sandwich the spin torque oscillator in a second direction which is parallel to the air-bearing surface and perpendicular to the first direction. The second shield is provided on a second side of the spin torque oscillator opposite to the first side.
    Type: Grant
    Filed: August 10, 2010
    Date of Patent: October 8, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Katsuhiko Koui, Mariko Kitazaki, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Soichi Oikawa, Akihiko Takeo
  • Patent number: 8547662
    Abstract: An example magnetic writing head includes a main magnetic pole, a coil to generate an ampere magnetic field to magnetize the main magnetic pole to cause the magnetized main magnetic pole to generate a magnetic field, and a laminated body. The laminated body includes a first magnetic layer having a coercivity lower than the magnetic field applied by the main magnetic pole and a second magnetic layer having a coercivity lower than the magnetic field applied by the main magnetic pole.
    Type: Grant
    Filed: July 3, 2012
    Date of Patent: October 1, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Junichi Akiyama, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Mariko Shimizu, Shuichi Murakami, Tadashi Kai
  • Publication number: 20130250456
    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: Application
    Filed: August 14, 2012
    Publication date: September 26, 2013
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kenichiro YAMADA, Yusuke TOMODA, Tomoko TAGUCHI, Katsuhiko KOUI
  • Publication number: 20130215532
    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: Application
    Filed: August 21, 2012
    Publication date: August 22, 2013
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoko TAGUCHI, Kenichiro YAMADA, Katsuhiko KOUI, Tomomi FUNAYAMA, Norihito FUJITA
  • Patent number: 8488373
    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: Grant
    Filed: October 3, 2011
    Date of Patent: July 16, 2013
    Assignees: TDK Corporation, Kabushiki Kaisha Toshiba
    Inventors: Kunliang Zhang, Min Li, Yuchen Zhou, Soichi Oikawa, Hitoshi Iwasaki, Kenichiro Yamada, Katsuhiko Koui
  • Patent number: 8472140
    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: Grant
    Filed: February 24, 2012
    Date of Patent: June 25, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Katsuhiko Koui, Mariko Kitazaki, Soichi Oikawa
  • 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
  • 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
  • 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
  • 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
  • Patent number: 8400734
    Abstract: An example magnetic recording head includes: a main magnetic pole; a laminated body; and a pair of electrodes. The laminated body includes a first magnetic layer having a coercivity lower than magnetic field applied by the main magnetic pole, a second magnetic layer having a coercivity lower than the magnetic field applied by the main magnetic pole, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. The pair of electrodes is operable to pass a current through the laminated body.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: March 19, 2013
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kenichiro Yamada, Hitoshi Iwasaki, Junichi Akiyama, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Mariko Shimizu, Shuichi Murakami, Tadashi Kai
  • 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
  • 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
  • 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
  • Publication number: 20120275060
    Abstract: An example magnetic head includes a recording magnetic 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 for applying a magnetic field to the spin torque oscillator.
    Type: Application
    Filed: July 10, 2012
    Publication date: November 1, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Mariko Shimizu, Hitoshi Iwasaki, Kenichiro Yamada, Junichi Akiyama, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita