Patents by Inventor Norihiro Okawa

Norihiro Okawa 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: 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
  • Publication number: 20160351212
    Abstract: A magnetic sensor having improved magnetic free layer stability and signal resolution. The magnetic sensor includes a weak magnetic spacer located between a magnetic free layer and a trailing magnetic shield. The weak magnetic spacer provides a desired weak magnetic coupling between the magnetic free layer and the trailing shield. This weak magnetic coupling reduces signal side lobe, thereby improving signal resolution. The weak magnetic spacer can be an alloy that includes magnetic and nonmagnetic elements. The magnetic elements can be one or more of Co, Fe and Ni. The nonmagnetic elements can be one or more of Hf, Ta, Nb and Zr.
    Type: Application
    Filed: May 30, 2015
    Publication date: December 1, 2016
    Inventors: Norihiro Okawa, Koujiro Komagaki
  • Patent number: 9349397
    Abstract: In one embodiment, a method for forming a magnetoresistive read head includes forming a fixed layer having a first ferromagnetic material that has a fixed direction of magnetization above a lower shield layer, forming a free layer having a second ferromagnetic material positioned above the fixed layer, the free layer having a non-fixed direction of magnetization, forming a first mask above the free layer, the first mask having a predetermined width based on a track width of a magnetic medium, etching the free layer down to the fixed layer using the first mask as a guide, wherein substantially none of the fixed layer is etched, and wherein the fixed layer extends beyond both sides of the free layer in a cross-track direction, and forming magnetic domain control films on both sides of the free layer in the cross-track direction, the magnetic domain control films including a soft magnetic material.
    Type: Grant
    Filed: March 26, 2014
    Date of Patent: May 24, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Masashi Hattori, Norihiro Okawa, Kouichi Nishioka, Kouji Okazaki
  • Patent number: 9330692
    Abstract: Embodiments disclosed herein generally relate to a TMR sensor for reading a recording from a magnetic recording medium using TMR, and in particular, to a magnetic capping structure of the TMR sensor. The sensor comprises a free layer and a magnetic capping structure. The magnetic capping structure comprises a ferromagnetic capping layer and an absorption layer formed on the ferromagnetic capping layer. The absorption layer is adapted to absorb molecules from the ferromagnetic capping layer and prevent the ferromagnetic capping layer from diffusing into the free layer.
    Type: Grant
    Filed: July 25, 2014
    Date of Patent: May 3, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Norihiro Okawa, Kojiro Komagaki
  • Publication number: 20160027458
    Abstract: Embodiments disclosed herein generally relate to a TMR sensor for reading a recording from a magnetic recording medium using TMR, and in particular, to a magnetic capping structure of the TMR sensor. The sensor comprises a free layer and a magnetic capping structure. The magnetic capping structure comprises a ferromagnetic capping layer and an absorption layer formed on the ferromagnetic capping layer. The absorption layer is adapted to absorb molecules from the ferromagnetic capping layer and prevent the ferromagnetic capping layer from diffusing into the free layer.
    Type: Application
    Filed: July 25, 2014
    Publication date: January 28, 2016
    Inventors: Norihiro OKAWA, Kojiro KOMAGAKI
  • Patent number: 9183858
    Abstract: The present disclosure generally relates to a read head sensor in a magnetic recording head. The read head sensor comprises a dual capping layer in a sensor stack that may reduce magnetic coupling so as to enhance magnetic bias field, e.g., domain control, in the read head sensor. Furthermore, an upper shield with multiple film stack having different film properties may also be utilized to enhance bias field generated to the read head sensor. Additionally, a coil structure may be positioned adjacent to a side shield to enhance bias field generation in the read head sensor.
    Type: Grant
    Filed: January 28, 2014
    Date of Patent: November 10, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Norihiro Okawa, Koujiro Komagaki
  • Publication number: 20150279392
    Abstract: In one embodiment, a method for forming a magnetoresistive read head includes forming a fixed layer having a first ferromagnetic material that has a fixed direction of magnetization above a lower shield layer, forming a free layer having a second ferromagnetic material positioned above the fixed layer, the free layer having a non-fixed direction of magnetization, forming a first mask above the free layer, the first mask having a predetermined width based on a track width of a magnetic medium, etching the free layer down to the fixed layer using the first mask as a guide, wherein substantially none of the fixed layer is etched, and wherein the fixed layer extends beyond both sides of the free layer in a cross-track direction, and forming magnetic domain control films on both sides of the free layer in the cross-track direction, the magnetic domain control films including a soft magnetic material.
    Type: Application
    Filed: March 26, 2014
    Publication date: October 1, 2015
    Applicant: HGST Netherlands B.V.
    Inventors: Masashi Hattori, Norihiro Okawa, Kouichi Nishioka, Kouji Okazaki
  • Publication number: 20150213816
    Abstract: The present disclosure generally relates to a read head sensor in a magnetic recording head. The read head sensor comprises a dual capping layer in a sensor stack that may reduce magnetic coupling so as to enhance magnetic bias field, e.g., domain control, in the read head sensor. Furthermore, an upper shield with multiple film stack having different film properties may also be utilized to enhance bias field generated to the read head sensor. Additionally, a coil structure may be positioned adjacent to a side shield to enhance bias field generation in the read head sensor.
    Type: Application
    Filed: January 28, 2014
    Publication date: July 30, 2015
    Applicant: HGST NETHERLANDS B.V.
    Inventors: Norihiro OKAWA, Koujiro KOMAGAKI
  • Patent number: 9030786
    Abstract: In one embodiment, a magnetic head includes a magnetoresistive sensor having a free layer and a soft magnetic layer adapted to control a magnetization direction of the free layer and a magnetic domain of the free layer, wherein a close-packed plane of the soft magnetic layer is positioned parallel to an air bearing surface (ABS) of the magnetic head. In another embodiment, a method for forming a magnetic head includes forming a magnetoresistive sensor having a free layer above a substrate and forming a soft magnetic layer adapted to control a magnetization direction of the free layer and a magnetic domain of the free layer, wherein a close-packed plane of the soft magnetic layer is positioned parallel or oblique to an ABS of the magnetic head.
    Type: Grant
    Filed: July 23, 2013
    Date of Patent: May 12, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Norihiro Okawa, Kouji Okazaki
  • Patent number: 8964336
    Abstract: In one embodiment, a magnetic head includes a sensor stack of thin films including a free layer; a hard bias structure comprising a first foundation layer, a second foundation layer formed on the first foundation layer and a hard bias layer formed above the second foundation layer, wherein portions of the first and second foundation layers positioned along a side wall of the sensor stack have a discrete island structure. Additional embodiments are also disclosed.
    Type: Grant
    Filed: September 6, 2012
    Date of Patent: February 24, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Norihiro Okawa, Koji Sakamoto, Koji Okazaki
  • Publication number: 20150029610
    Abstract: In one embodiment, a magnetic head includes a magnetoresistive sensor having a free layer and a soft magnetic layer adapted to control a magnetization direction of the free layer and a magnetic domain of the free layer, wherein a close-packed plane of the soft magnetic layer is positioned parallel to an air bearing surface (ABS) of the magnetic head. In another embodiment, a method for forming a magnetic head includes forming a magnetoresistive sensor having a free layer above a substrate and forming a soft magnetic layer adapted to control a magnetization direction of the free layer and a magnetic domain of the free layer, wherein a close-packed plane of the soft magnetic layer is positioned parallel or oblique to an ABS of the magnetic head.
    Type: Application
    Filed: July 23, 2013
    Publication date: January 29, 2015
    Applicant: HGST Netherlands B.V.
    Inventors: Norihiro Okawa, Kouji Okazaki
  • Publication number: 20140063647
    Abstract: In one embodiment, a magnetic head includes a sensor stack of thin films including a free layer; a hard bias structure comprising a first foundation layer, a second foundation layer formed on the first foundation layer and a hard bias layer formed above the second foundation layer, wherein portions of the first and second foundation layers positioned along a side wall of the sensor stack have a discrete island structure. Additional embodiments are also disclosed.
    Type: Application
    Filed: September 6, 2012
    Publication date: March 6, 2014
    Applicant: HGST NETHERLANDS B.V
    Inventors: Norihiro Okawa, Koji Sakamoto, Koji Okazaki
  • Patent number: 8630069
    Abstract: In one embodiment, a magnetic head includes a magnetoresistance effect sensor including a free layer, a hard bias magnetic film adapted for performing magnetic domain control of the free layer by biasing a magnetization direction of the free layer towards a predefined direction that is positioned on both sides of the free layer in a track-width direction, an upper shield positioned above the hard bias magnetic film and the magnetoresistance effect sensor; and an antiferromagnetic (AFM) layer positioned above the upper shield. The upper shield includes first and second upper shield layers, and an AFM coupling layer positioned between the first upper shield layer and the second upper shield layer that is adapted for antiferromagnetically coupling the first upper shield layer and the second upper shield layer, wherein a magnetization of the first upper shield layer is antiparallel with a magnetization of the hard magnetic bias layer.
    Type: Grant
    Filed: October 4, 2012
    Date of Patent: January 14, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Norihiro Okawa, Kouji Okazaki, Yoshibumi Matsuda, Hiroshi Akiyama
  • Patent number: 8373943
    Abstract: According to one embodiment, a method for producing a magnetic head includes depositing a first film above a substrate, etching a pattern into the first film, depositing a second film on the etched portion of the first film, and depositing a third film above the first and second film to form a multilayer magnetic film, wherein the second film is embedded between the first and third film in a portion of the first film that is removed. In another embodiment, a differential magnetic read head includes a magnetic multilayer film comprising a stack of a first magnetic sensor film and a second magnetic sensor film which are not magnetically connected and a hard magnetic film provided on both sides in a track width direction of the magnetic multilayer film for controlling a magnetic domain of the magnetic multilayer film. The hard magnetic film is a laminated structure as described above.
    Type: Grant
    Filed: November 8, 2010
    Date of Patent: February 12, 2013
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kan Yasui, Nobuo Yoshida, Katsuro Watanabe, Norihiro Okawa
  • Patent number: 8339753
    Abstract: A magnetic read head having a novel magnetic bias structure that provides improved magnetic biasing for improved free layer robustness and reduced Barkhausen noise. The bias structure includes hard magnetic layer formed over first and second under-layers. At least a portion of the first under-layer is formed as discrete islands of material, and the second under-layer is formed over the first under-layer. The first under-layer has a thickness of 0.25 to 0.75 nm. The novel seed layer structure causes hard magnetic layer to have a magnetic anisotropy that is substantially parallel with the free layer of the sensor stack even in regions adjacent to the sensor stack.
    Type: Grant
    Filed: October 11, 2011
    Date of Patent: December 25, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Norihiro Okawa, Koji Sakamoto, Koji Okazaki