Patents by Inventor Masashige Sato

Masashige 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: 9378759
    Abstract: Embodiments disclosed herein generally relate to a magnetic disk device employing a MAMR head. The MAMR head includes an STO. The STO comprises an underlayer, an SPL, an interlayer, an FGL, and a capping layer. The SPL is comprised of a high perpendicular magnetic anisotropy material. The SPL has a large effective perpendicular magnetic anisotropy field, and the SPL has a lower magnetic moment than the FGL. An applied current is adapted to flow in a direction from the FGL to the SPL resulting in the magnetization direction of the SPL being almost perpendicular to the FGL and anti-parallel to a head-gap magnetic field due to a relation between a first spin torque directed from the SPL to the FGL and a second spin torque directed from the FGL to the SPL.
    Type: Grant
    Filed: November 20, 2014
    Date of Patent: June 28, 2016
    Assignee: HGST NETHERLANDS B.V.
    Inventors: Keiichi Nagasaka, Yo Sato, Masashige Sato, Susumu Okamura, Masato Shiimoto, Masukazu Igarashi
  • Publication number: 20160148627
    Abstract: Embodiments disclosed herein generally relate to a magnetic disk device employing a MAMR head. The MAMR head includes an STO. The STO comprises an underlayer, an SPL, an interlayer, an FGL, and a capping layer. The SPL is comprised of a high perpendicular magnetic anisotropy material. The SPL has a large effective perpendicular magnetic anisotropy field, and the SPL has a lower magnetic moment than the FGL. An applied current is adapted to flow in a direction from the FGL to the SPL resulting in the magnetization direction of the SPL being almost perpendicular to the FGL and anti-parallel to a head-gap magnetic field due to a relation between a first spin torque directed from the SPL to the FGL and a second spin torque directed from the FGL to the SPL.
    Type: Application
    Filed: November 20, 2014
    Publication date: May 26, 2016
    Inventors: Keiichi NAGASAKA, Yo SATO, Masashige SATO, Susumu OKAMURA, Masato SHIIMOTO, Masukazu IGARASHI
  • 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
  • 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
  • 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: 9064508
    Abstract: The present disclosure generally relates to a structure for a perpendicular microwave-assisted magnetic recording head used in a magnetic disk drive. A first spin-torque oscillator and a second spin-torque oscillator are positioned between the main pole of a recording head and a trailing shield, and are separated by a spin torque shield layer. The first spin-torque oscillator comprises a first magnetic layer, a first non-magnetic interlayer, and a second magnetic layer. The second spin-torque oscillator comprises a third magnetic layer, a second non-magnetic interlayer, and a fourth magnetic layer. An applied current is adapted to flow in a direction from the second magnetic layer to the first magnetic layer, and from the fourth magnetic layer to the third magnetic layer.
    Type: Grant
    Filed: March 17, 2014
    Date of Patent: June 23, 2015
    Assignee: HGST NETHERLANDS B.V.
    Inventors: Masato Shiimoto, Masukaza Igarashi, Masashige Sato
  • Patent number: 8976493
    Abstract: A magnetic sensor having improved pinned layer robustness for improved reliability and having improved side shielding for improved track resolution at very high data densities. The sensor has a pinned layer structure with laterally extending wing portions that become thicker with increasing distance from the air bearing surface and has a side shield structure has a thickness that decreases with increasing distance from the air bearing surface.
    Type: Grant
    Filed: December 11, 2013
    Date of Patent: March 10, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Hideki Mashima, Tutomu Yasuda, Masashige Sato, Masahiko Hatatani
  • Patent number: 8570691
    Abstract: In one embodiment, a tunnel magnetoresistance (TMR) head includes a lead layer above a substrate, a seed layer above the lead layer, an antiferromagnetic (AFM) layer above the seed layer, a first ferromagnetic layer above the AFM layer, a second ferromagnetic layer above the first ferromagnetic layer, a coupling layer between the first and second ferromagnetic layers, the coupling layer causing a magnetization of the second ferromagnetic layer to be coupled to a magnetization of the first ferromagnetic layer, a fixed layer above the second ferromagnetic layer, an insertion layer adjacent the fixed layer or in the fixed layer, a barrier layer above the fixed layer, a free layer above the barrier layer, and a cap layer above the free layer. In another embodiment, the insertion layer is from about 0.05 nm to 0.3 nm in thickness and includes Ta, Ti, Hf, and/or Zr, and the free layer includes CoFeB.
    Type: Grant
    Filed: April 7, 2011
    Date of Patent: October 29, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Masashige Sato, Kojiro Komagaki
  • Patent number: 8514527
    Abstract: According to one embodiment, a magnetoresistive effect head includes a magnetically pinned layer having a direction of magnetization that is pinned, a free magnetic layer positioned above the magnetically pinned layer, the free magnetic layer having a direction of magnetization that is free to vary, and a barrier layer comprising an insulator positioned between the magnetically pinned layer and the free magnetic layer, wherein at least one of the magnetically pinned layer and the free magnetic layer has a layered structure, the layered structure including a crystal layer comprising one of: a CoFe magnetic layer or a CoFeB magnetic layer and an amorphous magnetic layer comprising CoFeB and an element selected from: Ta, Hf, Zr, and Nb, wherein the crystal layer is positioned closer to a tunnel barrier layer than the amorphous magnetic layer. In another embodiment, a magnetic data storage system includes the magnetoresistive effect head described above.
    Type: Grant
    Filed: November 29, 2010
    Date of Patent: August 20, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Kojiro Komagaki, Katsumi Hoshino, Masashige Sato, Hiroyuki Hoshiya
  • Publication number: 20120257298
    Abstract: In one embodiment, a tunnel magnetoresistance (TMR) head includes a lead layer above a substrate, a seed layer above the lead layer, an antiferromagnetic (AFM) layer above the seed layer, a first ferromagnetic layer above the AFM layer, a second ferromagnetic layer above the first ferromagnetic layer, a coupling layer between the first and second ferromagnetic layers, the coupling layer causing a magnetization of the second ferromagnetic layer to be coupled to a magnetization of the first ferromagnetic layer, a fixed layer above the second ferromagnetic layer, an insertion layer adjacent the fixed layer or in the fixed layer, a barrier layer above the fixed layer, a free layer above the barrier layer, and a cap layer above the free layer. In another embodiment, the insertion layer is from about 0.05 nm to 0.3 nm in thickness and includes Ta, Ti, Hf, and/or Zr, and the free layer includes CoFeB.
    Type: Application
    Filed: April 7, 2011
    Publication date: October 11, 2012
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masashige Sato, Kojiro Komagaki
  • Patent number: 8194362
    Abstract: A magnetoresistive effect device includes an underlayer, an antiferromagnetic layer, a first ferromagnetic layer, a nonmagnetic layer, and a second ferromagnetic layer which are multilayered in this order on a substrate. The underlayer is formed of a metal nitride, and the antiferromagnetic layer is formed of an antiferromagnetic material including Ir and Mn.
    Type: Grant
    Filed: July 23, 2010
    Date of Patent: June 5, 2012
    Assignee: Fujitsu Limited
    Inventors: Takahiro Ibusuki, Masashige Sato, Shinjiro Umehara
  • Patent number: 8184407
    Abstract: An underlying layer (2) made of NiFeN is disposed over the principal surface of a substrate. A pinning layer (3) made of antiferromagnetic material containing Ir and Mn is disposed on the underlying layer. A reference layer (4c) made of ferromagnetic material whose magnetization direction is fixed through exchange-coupling with the pinning layer directly or via another ferromagnetic material layer, is disposed over the pinning layer. A nonmagnetic layer (7) made of nonmagnetic material is disposed over the reference layer. A free layer (8) made of ferromagnetic material whose magnetization direction changes in dependence upon an external magnetic field, is disposed over the nonmagnetic layer.
    Type: Grant
    Filed: March 3, 2008
    Date of Patent: May 22, 2012
    Assignee: Fujitsu Limited
    Inventors: Takahiro Ibusuki, Masashige Sato, Shinjiro Umehara
  • Patent number: 8081404
    Abstract: A magnetoresistive element includes: a free layer made of a ferromagnetic material, the free layer configured to change the direction of magnetization under the influence of an external magnetic field; an insulating layer overlaid on the free layer, the insulating layer made of an insulating material; an amorphous reference layer overlaid on the insulating layer, the amorphous reference layer made of a ferromagnetic material, the amorphous reference layer configured to fix the magnetization in a predetermined direction; a crystal layer overlaid on the amorphous reference layer, the crystal layer containing crystal grains; a non-magnetic layer overlaid on the crystal layer, the non-magnetic layer containing crystal grains having grown from the crystal grains in the crystal layer; and a pinned layer overlaid on the non-magnetic layer, the pinned layer configured to fix the magnetization in a predetermined direction.
    Type: Grant
    Filed: August 27, 2009
    Date of Patent: December 20, 2011
    Assignee: Fujitsu Limited
    Inventors: Takahiro Ibusuki, Shinjiro Umehara, Masashige Sato
  • Patent number: 8072714
    Abstract: A barrier layer is disposed over a pinned layer made of ferromagnetic material having a fixed magnetization direction, the barrier layer having a thickness allowing electrons to transmit therethrough by a tunneling phenomenon. A first free layer is disposed over the barrier layer, the first free layer being made of amorphous or fine crystalline soft magnetic material which changes a magnetization direction under an external magnetic field. A second free layer is disposed over the first free layer, the second free layer being made of crystalline soft magnetic material which changes a magnetization direction under an external magnetic field and being exchange-coupled to the first free layer. A tunneling magnetoresistance device is provided which has good magnetic characteristics and can suppress a tunnel resistance change rate from being lowered.
    Type: Grant
    Filed: March 11, 2011
    Date of Patent: December 6, 2011
    Assignee: Fujitsu Limited
    Inventors: Masashige Sato, Shinjiro Umehara, Takahiro Ibusuki
  • Publication number: 20110164448
    Abstract: A barrier layer is disposed over a pinned layer made of ferromagnetic material having a fixed magnetization direction, the barrier layer having a thickness allowing electrons to transmit therethrough by a tunneling phenomenon. A first free layer is disposed over the barrier layer, the first free layer being made of amorphous or fine crystalline soft magnetic material which changes a magnetization direction under an external magnetic field. A second free layer is disposed over the first free layer, the second free layer being made of crystalline soft magnetic material which changes a magnetization direction under an external magnetic field and being exchange-coupled to the first free layer. A tunneling magnetoresistance device is provided which has good magnetic characteristics and can suppress a tunnel resistance change rate from being lowered.
    Type: Application
    Filed: March 11, 2011
    Publication date: July 7, 2011
    Applicant: Fujitsu Limited
    Inventors: Masashige Sato, Shinjiro Umehara, Takahiro Ibusuki
  • Publication number: 20110134563
    Abstract: According to one embodiment, a magnetoresistive effect head includes a magnetically pinned layer having a direction of magnetization that is pinned, a free magnetic layer positioned above the magnetically pinned layer, the free magnetic layer having a direction of magnetization that is free to vary, and a barrier layer comprising an insulator positioned between the magnetically pinned layer and the free magnetic layer, wherein at least one of the magnetically pinned layer and the free magnetic layer has a layered structure, the layered structure including a crystal layer comprising one of: a CoFe magnetic layer or a CoFeB magnetic layer and an amorphous magnetic layer comprising CoFeB and an element selected from: Ta, Hf, Zr, and Nb, wherein the crystal layer is positioned closer to a tunnel barrier layer than the amorphous magnetic layer. In another embodiment, a magnetic data storage system includes the magnetoresistive effect head described above.
    Type: Application
    Filed: November 29, 2010
    Publication date: June 9, 2011
    Inventors: Kojiro Komagaki, Katsumi Hoshino, Masashige Sato, Hiroyuki Hoshiya