Patents by Inventor Takahiro Ibusuki

Takahiro Ibusuki 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).

  • Publication number: 20240004000
    Abstract: Each of first and second magnetoresistance effect elements includes an upper electrode, a lower electrode, and a magnetoresistance effect multilayer body between the upper and lower electrodes. In the magnetoresistance effect multilayer body, a magnetized fixed layer having magnetization fixed in a certain direction, a first nonmagnetic layer, and a magnetized free layer whose magnetization direction changes according to a signal magnetic field are sequentially positioned. The upper electrode is provided on a side of the magnetized free layer opposite to the first nonmagnetic layer in a laminating direction of the magnetoresistance effect multilayer body. Each of the upper and lower electrodes includes a magnetic material film including a magnetic material.
    Type: Application
    Filed: September 13, 2023
    Publication date: January 4, 2024
    Inventor: Takahiro IBUSUKI
  • Patent number: 10096331
    Abstract: A magnetic read head is provided, comprising a bottom magnetic shield, a first free magnetic layer, a second free magnetic layer, and a top magnetic shield, arranged from bottom to top in this order in a stacking direction from a leading side to a trailing side of the read head. A non-soft bias layer is positioned below the top magnetic shield and on a back side of the first and the second free magnetic layers. The top magnetic shield has a unidirectional anisotropy, the magnetic moments of the top and the bottom magnetic shields are canted relative to a plane of the first and the second free magnetic layers, and the top and the bottom magnetic shields are decoupled from the non-soft bias layer and not magnetically coupled to a soft bias layer.
    Type: Grant
    Filed: September 19, 2017
    Date of Patent: October 9, 2018
    Assignee: Western Digital Technologies, Inc.
    Inventors: Norihiro Okawa, Koujiro Komagaki, Takahiro Ibusuki
  • Patent number: 10008224
    Abstract: A magnetic read element having an additional magnetic layer, “a floating magnetic shield”, formed as a part of a capping structure of a magnetoresistive element. The capping structure is formed over the magnetic free layer and includes a magnetic layer that is located between first and second non-magnetic layers. The magnetic layer can advantageously be formed with a high magnetic permeability for increased signal amplitude and increased signal resolution. In addition, because the magnetic layer of the capping layer structure acts as a magnetic shield, it can reduce effective magnetic gap spacing for increased signal resolution.
    Type: Grant
    Filed: March 11, 2016
    Date of Patent: June 26, 2018
    Assignee: Western Digital Technologies, Inc.
    Inventors: Takahiro Ibusuki, Kouji Kataoka, Takashi Wagatsuma, Norihiro Okawa, Yukimasa Okada
  • Publication number: 20180005652
    Abstract: A magnetic read head is provided, comprising a bottom magnetic shield, a first free magnetic layer, a second free magnetic layer, and a top magnetic shield, arranged from bottom to top in this order in a stacking direction from a leading side to a trailing side of the read head. A non-soft bias layer is positioned below the top magnetic shield and on a back side of the first and the second free magnetic layers. The top magnetic shield has a unidirectional anisotropy, the magnetic moments of the top and the bottom magnetic shields are canted relative to a plane of the first and the second free magnetic layers, and the top and the bottom magnetic shields are decoupled from the non-soft bias layer and not magnetically coupled to a soft bias layer.
    Type: Application
    Filed: September 19, 2017
    Publication date: January 4, 2018
    Inventors: Norihiro Okawa, Koujiro Komagaki, Takahiro Ibusuki
  • Patent number: 9799356
    Abstract: A magnetic read head is provided, comprising a bottom magnetic shield, a first free magnetic layer, a second free magnetic layer, and a top magnetic shield, arranged from bottom to top in this order in a stacking direction from a leading side to a trailing side of the read head. A soft bias layer is positioned below the top magnetic shield and on a back side of the first free magnetic layer and second free magnetic layer. The soft bias layer is directly coupled to the top magnetic shield, and the top magnetic shield has a unidirectional anisotropy, thereby reducing the incidence of soft bias magnetization reversal and avoiding hysteresis in the transfer curve.
    Type: Grant
    Filed: January 4, 2016
    Date of Patent: October 24, 2017
    Assignee: Western Digital Technologies, Inc.
    Inventors: Norihiro Okawa, Koujiro Komagaki, Takahiro Ibusuki
  • Publication number: 20170263273
    Abstract: A magnetic read element having an additional magnetic layer, “a floating magnetic shield”, formed as a part of a capping structure of a magnetoresistive element. The capping structure is formed over the magnetic free layer and includes a magnetic layer that is located between first and second non-magnetic layers. The magnetic layer can advantageously he formed with a high magnetic permeability for increased signal amplitude and increased signal resolution. In addition, because the magnetic layer of the capping layer structure acts as a magnetic shield, it can reduce effective magnetic gap spacing for increased signal resolution.
    Type: Application
    Filed: March 11, 2016
    Publication date: September 14, 2017
    Inventors: Takahiro Ibusuki, Kouji Kataoka, Takashi Wagatsuma, Norihiro Okawa, Yukimasa Okada
  • Publication number: 20170194023
    Abstract: A magnetic read head is provided, comprising a bottom magnetic shield, a first free magnetic layer, a second free magnetic layer, and a top magnetic shield, arranged from bottom to top in this order in a stacking direction from a leading side to a trailing side of the read head. A soft bias layer is positioned below the top magnetic shield and on a back side of the first free magnetic layer and second free magnetic layer. The soft bias layer is directly coupled to the top magnetic shield, and the top magnetic shield has a unidirectional anisotropy, thereby reducing the incidence of soft bias magnetization reversal and avoiding hysteresis in the transfer curve.
    Type: Application
    Filed: January 4, 2016
    Publication date: July 6, 2017
    Inventors: Norihiro Okawa, Koujiro Komagaki, Takahiro Ibusuki
  • Patent number: 9042060
    Abstract: In one embodiment, a magnetic head includes a lower shield, a magnetoresistive (MR) film positioned above the lower shield, the MR film including a pinned layer, an intermediate layer positioned above the pinned layer, and a free layer positioned above the intermediate layer, the free layer being configured for sensing data on a magnetic medium, wherein a track width of the MR film is defined by a width of the free layer in a cross-track direction, a bias layer positioned on both sides of the MR film in the cross-track direction, a track insulating film positioned on both sides of the MR film in the cross-track direction and between the MR film and the bias layer, and an upper shield positioned above the bias layer and the MR film, wherein a length of the free layer in an element height direction perpendicular to an air bearing surface of the magnetic head is less than a length of the pinned layer in the element height direction.
    Type: Grant
    Filed: September 25, 2013
    Date of Patent: May 26, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Nobuo Yoshida, Hideki Mashima, Norihiro Iwata, Takahiro Ibusuki
  • Publication number: 20150085395
    Abstract: In one embodiment, a magnetic head includes a lower shield, a magnetoresistive (MR) film positioned above the lower shield, the MR film including a pinned layer, an intermediate layer positioned above the pinned layer, and a free layer positioned above the intermediate layer, the free layer being configured for sensing data on a magnetic medium, wherein a track width of the MR film is defined by a width of the free layer in a cross-track direction, a bias layer positioned on both sides of the MR film in the cross-track direction, a track insulating film positioned on both sides of the MR film in the cross-track direction and between the MR film and the bias layer, and an upper shield positioned above the bias layer and the MR film, wherein a length of the free layer in an element height direction perpendicular to an air bearing surface of the magnetic head is less than a length of the pinned layer in the element height direction.
    Type: Application
    Filed: September 25, 2013
    Publication date: March 26, 2015
    Applicant: HGST Netherlands B.V.
    Inventors: Nobuo Yoshida, Hideki Mashima, Norihiro Iwata, Takahiro Ibusuki
  • Patent number: 8976492
    Abstract: In one embodiment, a magnetic head includes a lower shield, a read element positioned above the lower shield at a media-facing surface of the magnetic head, the read element having a free layer, an upper shield positioned above the read element, a first domain control layer having a direction of magnetization in a predetermined direction, the first domain control layer being configured to control a direction of magnetization of the free layer toward the predetermined direction, and a second domain control layer configured to have a magnetization in a same direction as the direction of magnetization of the first domain control layer, the second domain control layer being positioned above the first domain control layer, wherein the first domain control layer is a hard magnetic layer, and wherein the second domain control layer is a soft magnetic layer.
    Type: Grant
    Filed: October 29, 2013
    Date of Patent: March 10, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Kouji Kataoka, Takashi Wagatsuma, Katsumi Hoshino, Takahiro Ibusuki, Yukimasa Okada, Norihiro Ookawa
  • Patent number: 8867178
    Abstract: In one embodiment, a magnetic sensor comprises a read element and a magnetic-domain-control film positioned on both sides of the read element in a cross-track direction. The magnetic-domain-control film has a flare shape which causes the magnetic-domain-control film to flare away in an element height direction from the depthwise end of read element and extending in both directions away from the read element in a cross-track direction. In another embodiment, a method for forming a magnetic sensor includes forming a read element and forming a magnetic-domain-control film positioned on both sides of the read element in a cross-track direction, wherein the magnetic-domain-control film has a flare shape which causes the magnetic-domain-control film to flare away from the depthwise end of read element extending in both directions in a cross-track direction.
    Type: Grant
    Filed: October 16, 2012
    Date of Patent: October 21, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Takahiro Ibusuki, Hideki Mashima, Yuta Udo
  • Patent number: 8786988
    Abstract: A magnetic sensor having reduced read gap thickness, reduced signal noise and improved signal to noise ratio. The sensor includes a sensor stack and hard bias structures formed at either side of the sensor stack for biasing the free layer of the sensor. A protective layer is formed over a portion of the hard bias structure, however a portion of the hard bias structure extends upward toward the upper shield and is disposed between the protective layer and the sensor stack as a result of the process used to form the magnetic bias structure. This portion of the hard bias structure that extends toward the upper shield has a reduced magnetization relative to the rest of the hard bias structure so that it will not magnetically couple with the upper shield.
    Type: Grant
    Filed: May 15, 2012
    Date of Patent: July 22, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Hideki Mashima, Nobuo Yoshida, Takahiro Ibusuki, Tsutomu Yasuda
  • Publication number: 20140104723
    Abstract: In one embodiment, a magnetic sensor comprises a read element and a magnetic-domain-control film positioned on both sides of the read element in a cross-track direction. The magnetic-domain-control film has a flare shape which causes the magnetic-domain-control film to flare away in an element height direction from the depthwise end of read element and extending in both directions away from the read element in a cross-track direction. In another embodiment, a method for forming a magnetic sensor includes forming a read element and forming a magnetic-domain-control film positioned on both sides of the read element in a cross-track direction, wherein the magnetic-domain-control film has a flare shape which causes the magnetic-domain-control film to flare away from the depthwise end of read element extending in both directions in a cross-track direction.
    Type: Application
    Filed: October 16, 2012
    Publication date: April 17, 2014
    Applicant: HGST Netherlands B.V.
    Inventors: Takahiro Ibusuki, Hideki Mashima, Yuta Udo
  • Publication number: 20130308228
    Abstract: A magnetic sensor having reduced read gap thickness, reduced signal noise and improved signal to noise ratio. The sensor includes a sensor stack and hard bias structures formed at either side of the sensor stack for biasing the free layer of the sensor. A protective layer is formed over a portion of the hard bias structure, however a portion of the hard bias structure extends upward toward the upper shield and is disposed between the protective layer and the sensor stack as a result of the process used to form the magnetic bias structure. This portion of the hard bias structure that extends toward the upper shield has a reduced magnetization relative to the rest of the hard bias structure so that it will not magnetically couple with the upper shield.
    Type: Application
    Filed: May 15, 2012
    Publication date: November 21, 2013
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hideki Mashima, Nobuo Yoshida, Takahiro Ibusuki, Tsutomu Yasuda
  • Patent number: 8570690
    Abstract: A magnetic sensor having a novel hard bias structure that provides reduced gap spacing for increased data density. The magnetic sensor includes a sensor stack with first and second sides formed on a magnetic shield. A thin insulation layer is formed over the sides of the sensor stack and over the bottom shield. An under-layer comprising Cu—O is formed over the insulation layer and a hard magnetic bias layer is formed over the under-layer. The use of Cu—O as the under-layer allows the under-layer to be made thinner while still maintaining excellent magnetic properties in the hard bias layers formed there-over. This reduced thickness of the under-layer allows the gap spacing (spacing between the top and bottom magnetic shields) to be reduced, which in turn provides increased data density.
    Type: Grant
    Filed: June 20, 2011
    Date of Patent: October 29, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Susumu Okamura, Hiroyuki Hoshiya, Takahiro Ibusuki
  • Patent number: 8451565
    Abstract: In one embodiment, a magnetic head includes a lower shield layer, a sensor stack positioned above the lower shield layer, the sensor stack including a free layer, a layered hard bias magnet positioned above the lower shield layer and on both sides of the sensor stack in a track width direction, and an upper shield layer positioned above the hard bias magnet and the sensor stack. The hard bias magnet includes a perpendicular anisotropy film positioned above the lower shield layer and aligned with both sides of the sensor stack in the track width direction, wherein the perpendicular anisotropy film directs magnetic fields in a direction perpendicular to planes of formation thereof, and an in-plane anisotropy film positioned above the perpendicular anisotropy film, wherein the in-plane anisotropy film directs magnetic fields in a direction of planes of formation thereof.
    Type: Grant
    Filed: November 21, 2011
    Date of Patent: May 28, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Susumu Okamura, Takahiro Ibusuki
  • Publication number: 20130128381
    Abstract: In one embodiment, a magnetic head includes a lower shield layer, a sensor stack positioned above the lower shield layer, the sensor stack including a free layer, a layered hard bias magnet positioned above the lower shield layer and on both sides of the sensor stack in a track width direction, and an upper shield layer positioned above the hard bias magnet and the sensor stack. The hard bias magnet includes a perpendicular anisotropy film positioned above the lower shield layer and aligned with both sides of the sensor stack in the track width direction, wherein the perpendicular anisotropy film directs magnetic fields in a direction perpendicular to planes of formation thereof, and an in-plane anisotropy film positioned above the perpendicular anisotropy film, wherein the in-plane anisotropy film directs magnetic fields in a direction of planes of formation thereof.
    Type: Application
    Filed: November 21, 2011
    Publication date: May 23, 2013
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Susumu Okamura, Takahiro Ibusuki
  • Publication number: 20120320473
    Abstract: A magnetic sensor having a novel hard bias structure that provides reduced gap spacing for increased data density. The magnetic sensor includes a sensor stack with first and second sides formed on a magnetic shield. A thin insulation layer is formed over the sides of the sensor stack and over the bottom shield. An under-layer comprising Cu—O is formed over the insulation layer and a hard magnetic bias layer is formed over the under-layer. The use of Cu—O as the under-layer allows the under-layer to be made thinner while still maintaining excellent magnetic properties in the hard bias layers formed thereover. This reduced thickness of the under-layer allows the gap spacing (spacing between the top and bottom magnetic shields) to be reduced, which in turn provides increased data density.
    Type: Application
    Filed: June 20, 2011
    Publication date: December 20, 2012
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Susumu Okamura, Hiroyuki Hoshiya, Takahiro Ibusuki
  • 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