Patents by Inventor Yo Sato

Yo Sato 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: 9336797
    Abstract: The present disclosure generally relates to a high-frequency oscillator for use in a recording device having a microwave-assisted magnetic recording head. The microwave-assisted magnetic recording head achieves a large assist effect by using an extended spin torque oscillator disposed between a main magnetic pole and a pole opposite the main magnetic pole. The spin torque oscillator obtains a strong high-frequency magnetic field and comprises a first non-magnetic spin scatterer, a reference layer, a first non-magnetic spin transfer layer, a first magnetic field generating layer, a second non-magnetic spin transfer layer, a second magnetic field generating layer, and a second non-magnetic spin scatterer. The spin torque oscillator has a drive current flowing though in the direction from the first magnetic field generating layer to the reference layer.
    Type: Grant
    Filed: May 29, 2014
    Date of Patent: May 10, 2016
    Assignee: HGST NETHERLANDS B.V.
    Inventors: Masukazu Igarashi, Masato Matsubara, Keiichi Nagasaka, Yo Sato, Masato Shiimoto, Masashige Sato
  • Patent number: 9311934
    Abstract: Embodiments disclosed herein generally relate to a MAMR head. The MAMR head includes an STO and a current switching system electrically coupled to the STO. The current switching system can be used to optimize the STO frequency by changing the STO bias polarity, i.e., by changing the direction of the current flowing to the STO. As a result, the difference between the STO frequency and the magnetic media frequency is minimized, which improves recording capability of the MAMR head.
    Type: Grant
    Filed: July 24, 2015
    Date of Patent: April 12, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Masato Shiimoto, Masashige Sato, Masukazu Igarashi, Yo Sato, Masato Matsubara
  • Patent number: 9305574
    Abstract: Embodiments disclosed herein generally relate to a MAMR head. The MAMR head includes an STO. The STO has a first magnetic layer, a second magnetic layer and an interlayer disposed between the first and second magnetic layers. One of the first and second magnetic layers is made of a negative polarization material while the other magnetic layer is made of a positive polarization material. As a result, the magnetizations in the first and second magnetic layers are in the same direction when in oscillation, which suppresses the partial cancellation of the magnetizations in the first and second magnetic layers and strengthens the AC magnetic field.
    Type: Grant
    Filed: September 23, 2014
    Date of Patent: April 5, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Keiichi Nagasaka, Yo Sato, Masato Shiimoto, Masashige Sato, Masukazu Igarashi, Susumu Okamura
  • Publication number: 20160086623
    Abstract: Embodiments disclosed herein generally relate to a MAMR head. The MAMR head includes an STO. The STO has a first magnetic layer, a second magnetic layer and an interlayer disposed between the first and second magnetic layers. One of the first and second magnetic layers is made of a negative polarization material while the other magnetic layer is made of a positive polarization material. As a result, the magnetizations in the first and second magnetic layers are in the same direction when in oscillation, which suppresses the partial cancellation of the magnetizations in the first and second magnetic layers and strengthens the AC magnetic field.
    Type: Application
    Filed: September 23, 2014
    Publication date: March 24, 2016
    Inventors: Keiichi NAGASAKA, Yo SATO, Masato SHIIMOTO, Masashige SATO, Masukazu IGARASHI, Susumu OKAMURA
  • Patent number: 9230569
    Abstract: In one embodiment, a magnetic head includes a main magnetic pole positioned configured to generate a writing magnetic field when current is applied to a write coil, and a spin torque oscillator (STO) located adjacent the main magnetic pole, the STO being configured to generate a high frequency magnetic field when current is applied thereto, wherein the high frequency magnetic field is generated simultaneously to the writing magnetic field to assist in reversing magnetization of a magnetic recording medium. The STO includes: a spin polarization layer (SPL), a field generation layer (FGL) positioned adjacent the SPL, and one or more interlayers positioned between the SPL and the FGL, and a magnetization easy axis of the SPL is positioned in an in-plane direction such that the SPL has no perpendicular magnetic anisotropy.
    Type: Grant
    Filed: November 26, 2014
    Date of Patent: January 5, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Masato Shimoto, Masukazu Igarashi, Keiichi Nagasaka, Yo Sato, Susumu Okamura, Masashige Sato
  • Patent number: 9230597
    Abstract: In one embodiment, a magnetic head includes a main pole configured to write data to a magnetic medium, a trailing shield positioned on a trailing side of the main pole, and a STO between the main pole and the trailing shield, wherein the STO includes a laminated structure having a FGL, a spun polarization layer (SPL), and a non-magnetic spacer positioned between the FGL and the SPL, wherein the FGL includes a laminated structure having one or more layers of a CoFe alloy and a Heusler alloy alternately laminated in this order from an end of the FGL closest to the non-magnetic spacer. In another embodiment, a method is presented for forming such a magnetic head utilizing a FGL that includes a laminated structure baying layers of a CoFe alloy and a Heusler alloy alternately laminated in this order from an end of the FGL closest to the non-magnetic spacer.
    Type: Grant
    Filed: November 1, 2013
    Date of Patent: January 5, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Masato Shimoto, Keiichi Nagasaka, Masato Matsubara, Yo Sato
  • Publication number: 20150348574
    Abstract: The present disclosure generally relates to a high-frequency oscillator for use in a recording device having a microwave-assisted magnetic recording head. The microwave-assisted magnetic recording head achieves a large assist effect by using an extended spin torque oscillator disposed between a main magnetic pole and a pole opposite the main magnetic pole. The spin torque oscillator obtains a strong high-frequency magnetic field and comprises a first non-magnetic spin scatterer, a reference layer, a first non-magnetic spin transfer layer, a first magnetic field generating layer, a second non-magnetic spin transfer layer, a second magnetic field generating layer, and a second non-magnetic spin scatterer. The spin torque oscillator has a drive current flowing though in the direction from the first magnetic field generating layer to the reference layer.
    Type: Application
    Filed: May 29, 2014
    Publication date: December 3, 2015
    Applicant: HGST NETHERLANDS B.V.
    Inventors: Masukazu IGARASHI, Masato MATSUBARA, Keiichi NAGASAKA, Yo SATO, Masato SHIIMOTO, Masashige SATO
  • Publication number: 20150228295
    Abstract: The embodiments disclosed generally relate to an STO structure for a magnetic head. The STO structure has an FGL having a greater thickness than the SPL. The SPL may have multiple layers. In one embodiment, a MAMR head comprises a main pole; a trailing shield; and an STO coupled between the main pole and the trailing shield. The STO includes: a first magnetic layer having a first thickness; a non-magnetic spacer layer coupled to the first magnetic layer; and a second magnetic layer having a second thickness and coupled to the non-magnetic spacer layer, wherein the first thickness is greater than the second thickness, wherein a current is charged from the first magnetic layer to the second magnetic layer, and wherein a vertical magnetic anisotropy field of the second magnetic film is less than 0 kOe.
    Type: Application
    Filed: February 12, 2014
    Publication date: August 13, 2015
    Applicant: HGST Netherlands B.V.
    Inventors: Masato SHIIMOTO, Masukaza IGARASHI, Keiichi NAGASAKA, Yo SATO
  • Patent number: 9099107
    Abstract: In one embodiment, a spin torque oscillator (STO) includes a reference layer having a magnetization that is capable of free in-plane rotation, a field generation layer (FGL) including at least one magnetic film having an easy magnetization plane effectively in a film plane, wherein a magnetization of the FGL is capable of in-plane rotation, and a stabilizing layer (STL) positioned on a side of the FGL opposite the reference layer, the STL including a magnetic film having an easy magnetization plane effectively in a film plane, wherein a magnetization of the STL is capable of in-plane rotation, wherein a product of a saturation magnetization of the STL multiplied by a thickness of the STL is less than half a product of a magnetization of the FGL multiplied by a thickness of the FGL.
    Type: Grant
    Filed: January 23, 2015
    Date of Patent: August 4, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Masukazu Igarashi, Keiichi Nagasaka, Susumu Okamura, Yo Sato, Masashige Sato, Masato Shimoto
  • Patent number: 9030777
    Abstract: A spin torque oscillator generates a strong high-frequency magnetic field stably and has high reliability. A magnetic recording head includes a main magnetic pole and a spin torque oscillator. A magnetization control layer is antiferromagnetically coupled via a non-magnetic coupling layer with an interface contacting a high-frequency magnetic field generation layer of the spin torque oscillator.
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: May 12, 2015
    Assignee: Hitachi, Ltd.
    Inventor: Yo Sato
  • Publication number: 20150124347
    Abstract: In one embodiment, a magnetic head includes a main pole configured to write data to a magnetic medium, a trailing shield positioned on a trailing side of the main pole, and a STO between the main pole and the trailing shield, wherein the STO includes a laminated structure having a FGL, a spun polarization layer (SPL), and a non-magnetic spacer positioned between the FGL and the SPL, wherein the FGL includes a laminated structure having one or more layers of a CoFe alloy and a Heusler alloy alternately laminated in this order from an end of the FGL closest to the non-magnetic spacer. In another embodiment, a method is presented for forming such a magnetic head utilizing a FGL that includes a laminated structure baying layers of a CoFe alloy and a Heusler alloy alternately laminated in this order from an end of the FGL closest to the non-magnetic spacer.
    Type: Application
    Filed: November 1, 2013
    Publication date: May 7, 2015
    Applicant: HGST Netherlands B.V.
    Inventors: Masato Shimoto, Keiichi Nagasaka, Masato Matsubara, Yo Sato
  • Patent number: 9007723
    Abstract: In one embodiment, a microwave-assisted magnetic recording (MAMR) head includes a main pole configured to write data to a magnetic medium using a write magnetic field, a write coil, wherein the write magnetic field is produced by the main pole upon a recording current, Iw, being provided to the write coil, and a spin torque oscillator (STO) positioned near the main pole, the STO being configured to provide a high-frequency assistance magnetic field to the magnetic medium upon a STO drive current, ISTO, being provided to the STO, wherein the STO drive current, ISTO, is ramped-up prior to the recording current, Iw, being provided to the write coil in order to begin a write operation for writing data to the magnetic medium. A method of operation for the MAMR head and an apparatus including the MAMR head are also described according to additional embodiments.
    Type: Grant
    Filed: December 13, 2013
    Date of Patent: April 14, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Masukazu Igarashi, Masato Shiimoto, Masato Matsubara, Yo Sato, Kenji Sugiura
  • Patent number: 9007722
    Abstract: To uniformly determine the positional relationship between a main magnetic pole and a spin torque oscillator while independently optimizing the main magnetic pole and the spin torque oscillator. On a trailing end surface of a main magnetic pole, a step is provided at the boundary between the main magnetic pole and a gap material disposed on both sides thereof, and a spin torque oscillator is formed on the step. The spin torque oscillator is effectively separated into two regions by utilizing the step. Further, a part of the spin torque oscillator is removed so as to disable the unwanted region, thereby realizing a self-alignment type high frequency magnetic field assisted magnetic recording head structure such that the positions of the end portions of the main magnetic pole and the spin torque oscillator are aligned.
    Type: Grant
    Filed: August 16, 2013
    Date of Patent: April 14, 2015
    Assignee: Hitachi, Ltd.
    Inventors: Junichiro Shimizu, Kikuo Kusukawa, Yo Sato, Masukazu Igarashi
  • Patent number: 9007721
    Abstract: A spin torque oscillator is provided which is adapted to high data transfer rates and which can perform assisted magnetic recording of sufficient magnitude. A spin torque oscillator is provided with a stacked spin injection layer and a high frequency magnetic field generation layer. The stacked spin injection layer has a stacked structure in which a first magnetic layer, a coupling layer, and a second magnetic layer are stacked in the order mentioned from a far side as viewed from the high frequency magnetic field generation layer. Magnetization of the first magnetic layer and magnetization of the second magnetic layer are coupled antiparallel to each other. A polarity of the magnetization of the second magnetic layer is reversed temporally earlier than a magnetic field polarity reversal of a leakage magnetic field from the main magnetic pole.
    Type: Grant
    Filed: August 2, 2013
    Date of Patent: April 14, 2015
    Assignee: Hitachi, Ltd.
    Inventors: Yo Sato, Katsuro Watanabe, Keizou Katou, Masukazu Igarashi
  • Patent number: 8953282
    Abstract: In a Spin Torque Oscillator (STO) comprising an underlayer, a first magnetic layer disposed on the underlayer, a non-magnetic intermediate layer disposed on the first magnetic layer, and a second magnetic layer disposed on the non-magnetic intermediate layer, the non-magnetic intermediate layer is a non-magnetic alloy containing 50 at % or more of at least one kind of element selected from a first group consisting of Cu, Ag, and Au, and further at least 0.1 at % or more in total of at least one kind of element selected from a second group consisting of Cu, Ag, Au, Cr, Ti, Zr, Hf, V, Nb, Ta, Ru, Os, Pd, Pt, Rh, and Ir that does not overlap with the element from the first group.
    Type: Grant
    Filed: August 6, 2013
    Date of Patent: February 10, 2015
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihiro Shiroishi, Katsuro Watanabe, Yo Sato
  • Patent number: 8854768
    Abstract: To realize a highly reliable magnetic head for a high-frequency magnetic field assisted recording system by preventing current crowding in an oscillator and increasing the current resistance of the oscillator. Between a main pole that generates a recording magnetic field and a trailing shield, an oscillator that includes a non-magnetic metal layer, a spin injection pinned layer, an intermediate layer, and a high-frequency magnetic field generation layer and that generates a high-frequency magnetic field is disposed. The non-magnetic metal layer adjacent to the main pole is tapered with the width gradually increasing from the trailing side toward the leading side.
    Type: Grant
    Filed: January 29, 2014
    Date of Patent: October 7, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Kenji Sugiura, Yo Sato, Masukazu Igarashi, Katsuro Watanabe
  • Patent number: 8830627
    Abstract: In a magnetic head of a high-frequency magnetic field assisted recording system, a width of a high-frequency magnetic field from an oscillator is decreased to enhance an oscillation frequency, in order to realize a high-density recording. An oscillator provided near a main pole, which generates a recording magnetic field, for generating a high-frequency magnetic field is patterned by a conventional photolithography, and then, an oxidation, nitridation, or oxynitridation is performed on the side face in a track width direction. With this process, an oxide layer, a nitride layer, or an oxynitride layer, which is made of a material of the oscillator, is formed on the side face of the oscillator in the track width direction, and the shape of the oscillator is formed to be semi-circular.
    Type: Grant
    Filed: January 7, 2013
    Date of Patent: September 9, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Kenji Sugiura, Katsuro Watanabe, Masukazu Igarashi, Yo Sato
  • Patent number: 8824103
    Abstract: The strength of a magnetic field applied from a main pole to an oscillator and the strength of a magnetic field applied from the main pole to a recording medium are improved in a magnetic recording head for microwave assisted recording. In the magnetic recording head according to the present invention, an interval between the main pole and a trailing shield at a place in a position above an air bearing surface is larger than an interval between the main pole and the trailing shield on the air bearing surface.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: September 2, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Masato Shiimoto, Kenji Sugiura, Mikito Sugiyama, Isao Nunokawa, Yo Sato, Katsuro Watanabe, Kazuhiko Hosomi, Nobuo Yoshida
  • Publication number: 20140211340
    Abstract: To realize a highly reliable magnetic head for a high-frequency magnetic field assisted recording system by preventing current crowding in an oscillator and increasing the current resistance of the oscillator. Between a main pole that generates a recording magnetic field and a trailing shield, an oscillator that includes a non-magnetic metal layer, a spin injection pinned layer, an intermediate layer, and a high-frequency magnetic field generation layer and that generates a high-frequency magnetic field is disposed. The non-magnetic metal layer adjacent to the main pole is tapered with the width gradually increasing from the trailing side toward the leading side.
    Type: Application
    Filed: January 29, 2014
    Publication date: July 31, 2014
    Applicant: HITACHI, LTD.
    Inventors: Kenji SUGIURA, Yo SATO, Masukazu IGARASHI, Katsuro WATANABE
  • Patent number: 8778515
    Abstract: Embodiments of the present invention provide a practical magneto-resistive effect element for CPP-GMR, which exhibits appropriate resistance-area-product and high magnetoresistance change ratio, and meets the demand for a narrow read gap. Certain embodiments of a magneto-resistive effect element in accordance with the present invention include a pinned ferromagnetic layer containing a first ferromagnetic film having a magnetization direction fixed in one direction, a free ferromagnetic layer containing a second ferromagnetic film having a magnetization direction varying in response to an external magnetic field, an intermediate layer provided between the pinned ferromagnetic layer and the free ferromagnetic layer, and a current confinement layer for confining a current. At least one of the pinned ferromagnetic layer or the free ferromagnetic layer includes a highly spin polarized layer.
    Type: Grant
    Filed: November 21, 2008
    Date of Patent: July 15, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Yo Sato, Katsumi Hoshino, Hiroyuki Hoshiya