Patents by Inventor Takumi Yanagisawa

Takumi Yanagisawa 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: 9129622
    Abstract: A magnetoresistive effect element that prevents a recording medium from deteriorating by effectively inhibiting erroneous writing to a medium or the like includes a magnetoresistive effect part, and an upper shield layer and a lower shield layer that are laminated and formed in a manner sandwiching the magnetoresistive effect part from above and below, and is in a current perpendicular to plane (CPP) structure in which a sense current is applied in a lamination direction.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: September 8, 2015
    Assignee: TDK Corporation
    Inventors: Takahiko Machita, Naomichi Degawa, Takekazu Yamane, Takumi Yanagisawa, Satoshi Miura, Kenta Hamamoto, Minoru Ota, Kenzo Makino, Shohei Kawasaki
  • Patent number: 8896974
    Abstract: A thin film magnetic head includes a spin valve film that includes a magnetization free layer, a magnetization pinned layer and a non-magnetic spacer layer that is disposed between the magnetization free and pinned layers, and a pair of side layers that are disposed at both sides of the spin valve film in a track width direction and at least in the vicinity of the magnetization free layer and the magnetization pinned layer. Each of the side layers has a bias magnetic field application layer that includes a soft magnetic layer and applies a bias magnetic field in the track width direction to the magnetization free layer, and a gap layer that is positioned between the spin valve film and the bias magnetic field application layer, and the side layers have compression stresses at least in the vicinity of the magnetization pinned layer.
    Type: Grant
    Filed: March 29, 2013
    Date of Patent: November 25, 2014
    Assignee: TDK Corporation
    Inventors: Shohei Kawasaki, Shuji Okame, Takayasu Kanaya, Satoshi Miura, Kenzo Makino, Takumi Yanagisawa, Takahiko Machita, Masashi Sano, Hideyuki Ukita
  • Patent number: 8891208
    Abstract: An MR element suppressing a false writing into a medium with an MR part has a CPP structure. The MR part includes a nonmagnetic intermediate layer and first and second ferromagnetic layers so as to interpose the nonmagnetic intermediate layer. First and second shield layers respectively have an inclining magnetization structure of which a magnetization is inclined with regard to a track width direction. The first and second ferromagnetic layers are respectively, magnetically coupled with the first and second shield layers. A magnetization direction adjustment layer for adjusting at least a magnetization direction of the first ferromagnetic layer is positioned at a rear end surface side of the first ferromagnetic layer, which is opposite to a front end surface receiving a magnetic field detected in the MR part.
    Type: Grant
    Filed: March 29, 2013
    Date of Patent: November 18, 2014
    Assignee: TDK Corporation
    Inventors: Naomichi Degawa, Takahiko Machita, Takekazu Yamane, Takumi Yanagisawa, Satoshi Miura, Kenta Hamamoto, Minoru Ota, Kenzo Makino, Shohei Kawasaki
  • Publication number: 20140293475
    Abstract: An MR element suppressing a false writing into a medium with an MR part has a CPP structure. The MR part includes a nonmagnetic intermediate layer and first and second ferromagnetic layers so as to interpose the nonmagnetic intermediate layer. First and second shield layers respectively have an inclining magnetization structure of which a magnetization is inclined with regard to a track width direction. The first and second ferromagnetic layers are respectively, magnetically coupled with the first and second shield layers. A magnetization direction adjustment layer for adjusting at least a magnetization direction of the first ferromagnetic layer is positioned at a rear end surface side of the first ferromagnetic layer, which is opposite to a front end surface receiving a magnetic field detected in the MR part.
    Type: Application
    Filed: March 29, 2013
    Publication date: October 2, 2014
    Inventors: Naomichi DEGAWA, Takahiko MACHITA, Takekazu YAMANE, Takumi YANAGISAWA, Satoshi MIURA, Kenta HAMAMOTO, Minoru OTA, Kenzo MAKINO, Shohei KAWASAKI
  • Publication number: 20140268405
    Abstract: A magnetoresistive effect element that prevents a recording medium from deteriorating by effectively inhibiting erroneous writing to a medium or the like includes a magnetoresistive effect part, and an upper shield layer and a lower shield layer that are laminated and formed in a manner sandwiching the magnetoresistive effect part from above and below, and is in a current perpendicular to plane (CPP) structure in which a sense current is applied in a lamination direction.
    Type: Application
    Filed: March 15, 2013
    Publication date: September 18, 2014
    Inventors: Takahiko MACHITA, Naomichi DEGAWA, Takekazu YAMANE, Takumi YANAGISAWA, Satoshi MIURA, Kenta HAMAMOTO, Minoru OTA, Kenzo MAKINO, Shohei KAWASAKI
  • Patent number: 8677607
    Abstract: The method according to the present invention includes the steps of: sequentially applying a plurality of different voltages to an MR element and sequentially detecting output signals from the MR element; and eliminating the MR element as a defective product when an evaluation value, based on a difference of SN ratios of the output signals from the MR element respectively obtained for each applied voltage, is less than a threshold value, and selecting the MR element as a non-defective product when the evaluation value is greater than or equal to the threshold value.
    Type: Grant
    Filed: March 7, 2008
    Date of Patent: March 25, 2014
    Assignee: TDK Corporation
    Inventors: Takumi Yanagisawa, Masaru Hirose, Shunji Saruki
  • Patent number: 8552328
    Abstract: The invention provides a method for fixing up the deterioration of a magneto-resistive effect device. A hard disk system is provided in it with a head heating means for heating a thin-film magnetic head, and by that head heating means, a defective site of the magneto-resistive effect device, which occurs as the hard disk system is in operation and is confined in a quasi-stable state, is fixed up in such a way as to return back to its own normal stable state. Thus, the deteriorated site of the magneto-resistive effect device (reproducing device) in the thin-film magnetic head, which is caused by the so-called thermal asperity as the hard disk system is in operation, is fixed up while it remains built in the hard disk system, i.e., without dismantling the hard disk system.
    Type: Grant
    Filed: December 28, 2007
    Date of Patent: October 8, 2013
    Assignee: TDK Corporation
    Inventors: Takumi Yanagisawa, Yosuke Antoku, Yoshikazu Sawada
  • Patent number: 8462467
    Abstract: A thin film magnetic head includes: a magneto resistance effect film of which electrical resistance varies corresponding to an external magnetic field; a pair of shields provided on both sides in a manner of sandwiching the MR film in a direction that is orthogonal to a film surface of the MR film; an anisotropy providing layer that provides exchange anisotropy to a first shield of the pair of shields in order to magnetize the first shield in a desired direction, and that is disposed on the opposite side from the MR film with respect to the first shield; and side shields that are disposed on both sides of the MR film in a track width direction and that include soft magnetic layers magnetically connected with the first shield.
    Type: Grant
    Filed: October 8, 2010
    Date of Patent: June 11, 2013
    Assignee: TDK Corporation
    Inventors: Takumi Yanagisawa, Yasushi Nishioka, Takahiko Machita, Satoshi Miura, Takayasu Kanaya, Kenzo Makino, Yoshikazu Sawada, Takekazu Yamane, Naomichi Degawa, Kosuke Tanaka, Soji Koide, Daisuke Miyauchi
  • Patent number: 8437106
    Abstract: A thin film magnetic head includes; an MR film that includes a pinned layer of which a magnetization direction is pinned, a free layer of which a magnetization direction varies, and a spacer that is disposed therebetween; a pair of shields that are disposed on both sides sandwiching the MR film in a direction orthogonal to a film surface of the MR film; and an anisotropy providing layer that provides anisotropy to a first shield so that the first shield is magnetized in a desired direction, and that is disposed on an opposite side from the MR film with respect to the first shield. The MR film includes a magnetic coupling layer that is disposed between the first shield and the free layer and that magnetically couples the first shield with the free layer.
    Type: Grant
    Filed: October 8, 2010
    Date of Patent: May 7, 2013
    Assignee: TDK Corporation
    Inventors: Takumi Yanagisawa, Yasushi Nishioka, Takahiko Machita, Satoshi Miura, Takayasu Kanaya, Kenzo Makino, Yoshikazu Sawada, Takekazu Yamane, Naomichi Degawa, Kosuke Tanaka, Soji Koide, Daisuke Miyauchi
  • Patent number: 8402635
    Abstract: A method of manufacturing a magnetic head, including a magneto resistance effect (MR) element that reads a magnetic recording medium, is disclosed. A multilayer film is formed on a shield layer. Unnecessary portions of the multilayer film are removed from both sides of the MR element in a first direction orthogonal to a lamination direction of the multilayer film and parallel to the MR element surface facing the magnetic recording medium. An insulating layer is formed on a surface exposed by removal of the unnecessary portions. An integrated soft magnetic layer covering both sides of the MR element in the first direction and an upper side of the MR element is formed, thereby configuring a second shield layer. An anisotropy application layer is formed on the second shield layer, thereby providing exchange anisotropy to the soft magnetic layer, and magnetizing the soft magnetic layer in a predetermined direction.
    Type: Grant
    Filed: March 21, 2011
    Date of Patent: March 26, 2013
    Assignee: TDK Corporation
    Inventors: Naomichi Degawa, Takumi Yanagisawa, Satoshi Miura, Yoshikazu Sawada, Takahiko Machita, Kenzo Makino, Takekazu Yamane, Shohei Kawasaki
  • Publication number: 20130000103
    Abstract: The method according to the present invention includes the steps of: sequentially applying a plurality of different voltages to an MR element and sequentially detecting output signals from the MR element; and eliminating the MR element as a defective product when an evaluation value, based on a difference of SN ratios of the output signals from the MR element respectively obtained for each applied voltage, is less than a threshold value, and selecting the MR element as a non-defective product when the evaluation value is greater than or equal to the threshold value.
    Type: Application
    Filed: March 7, 2008
    Publication date: January 3, 2013
    Applicant: TDK CORPORATION
    Inventors: Takumi YANAGISAWA, Masaru HIROSE, Shunji SARUKI
  • Publication number: 20120250189
    Abstract: A magnetic head that reads information of a magnetic recording medium is provided. The magnetic head according to one embodiment includes: an MR element, formed with multilayer films, of which an electrical resistance changes according to an external magnetic field; a first shield layer that is disposed on a lower side in an lamination direction of the MR element; a second shield layer that is disposed on an upper side in the lamination direction of the MR element, and that applies voltage to the MR element together with the first shield layer; and side shield layers that are disposed on both sides of the MR element in a truck width direction. The side shield layers include soft magnetic layers and hard magnetic layers magnetized in a predetermined direction.
    Type: Application
    Filed: March 29, 2011
    Publication date: October 4, 2012
    Applicant: TDK Corporation
    Inventors: Naomichi DEGAWA, Takumi Yanagisawa, Satoshi Miura, Yoshikazu Sawada, Takahiko Machita, Kenzo Makino, Takekazu Yamane, Shohei Kawasaki
  • Publication number: 20120240390
    Abstract: A method of manufacturing a magnetic head that includes a magneto resistance effect (MR) element of which an electrical resistance changes according to an external magnetic field and shield layers surrounding the MR element, and that reads information of a magnetic recording medium is provided.
    Type: Application
    Filed: March 21, 2011
    Publication date: September 27, 2012
    Applicant: TDK Corporation
    Inventors: Naomichi Degawa, Takumi Yanagisawa, Satoshi Miura, Yoshikazu Sawada, Takahiko Machita, Kenzo Makino, Takekazu Yamane, Shohei Kawasaki
  • Patent number: 8182705
    Abstract: A method for producing a thin film magnetic head including a magnetoresistive effect element (MR element) that has a magnetic sensor multi-layered film with a polygonal shape such that a vertex angle faces an air bearing surface (ABS) and a tip of the vertex angle is cut when the magnetic sensor multi-layered film is viewed from an X-Y plane that is parallel to a plane of a lower shield electrode layer includes a step for stopping a lapping process by using a measurement point in which a resistance value is steeply increased while the lapping face is gradually approaching the vertex angle of polygonal shape by lapping from the ABS side. Therefore, an excellent effect in which an ultra narrow track width that exceeds limits of photolithography technology can be securely and constantly formed is obtained.
    Type: Grant
    Filed: October 30, 2009
    Date of Patent: May 22, 2012
    Assignee: TDK Corporation
    Inventors: Kosuke Tanaka, Daisuke Miyauchi, Takumi Yanagisawa
  • Publication number: 20120087045
    Abstract: A thin film magnetic head includes; an MR film that includes a pinned layer of which a magnetization direction is pinned, a free layer of which a magnetization direction varies, and a spacer that is disposed therebetween; a pair of shields that are disposed on both sides sandwiching the MR film in a direction orthogonal to a film surface of the MR film; and an anisotropy providing layer that provides anisotropy to a first shield so that the first shield is magnetized in a desired direction, and that is disposed on an opposite side from the MR film with respect to the first shield. The MR film includes a magnetic coupling layer that is disposed between the first shield and the free layer and that magnetically couples the first shield with the free layer.
    Type: Application
    Filed: October 8, 2010
    Publication date: April 12, 2012
    Applicant: TDK Corporation
    Inventors: Takumi Yanagisawa, Yasushi Nishioka, Takahiko Machita, Satoshi Miura, Takayasu Kanaya, Kenzo Makino, Yoshikazu Sawada, Takekazu Yamane, Naomichi Degawa, Kosuke Tanaka, Soji Koide, Daisuke Miyauchi
  • Publication number: 20120087046
    Abstract: A thin film magnetic head includes: a magneto resistance effect film of which electrical resistance varies corresponding to an external magnetic field; a pair of shields provided on both sides in a manner of sandwiching the MR film in a direction that is orthogonal to a film surface of the MR film; an anisotropy providing layer that provides exchange anisotropy to a first shield of the pair of shields in order to magnetize the first shield in a desired direction, and that is disposed on the opposite side from the MR film with respect to the first shield; and side shields that are disposed on both sides of the MR film in a track width direction and that include soft magnetic layers magnetically connected with the first shield.
    Type: Application
    Filed: October 8, 2010
    Publication date: April 12, 2012
    Applicant: TDK Corporation
    Inventors: Takumi Yanagisawa, Yasushi Nishioka, Takahiko Machita, Satoshi Miura, Takayasu Kanaya, Kenzo Makino, Yoshikazu Sawada, Takekazu Yamane, Naomichi Degawa, Kosuke Tanaka, Soji Koide, Daisuke Miyauchi
  • Patent number: 8054587
    Abstract: An MR element includes a lower shield layer, a magnetization free function part stacked on the lower shield layer, an upper shield layer stacked on the magnetization free function part, a nonmagnetic intermediate layer stacked on a surface, that is opposite to a magnetically sensitive surface, of the magnetization free function part, and a magnetization fixed function part stacked on the nonmagnetic intermediate layer. The nonmagnetic intermediate layer and the magnetization fixed function part are formed only within an outer region of the magnetization free function part, located opposite side to the magnetically sensitive surface.
    Type: Grant
    Filed: January 9, 2009
    Date of Patent: November 8, 2011
    Assignee: TDK Corporation
    Inventor: Takumi Yanagisawa
  • Patent number: 8023214
    Abstract: A reproducing method of reproducing magnetic information written in each of bits of a recording medium using a magnetic head having a reading element configured to measure external magnetic field intensity includes moving, measuring and specifying steps. In the moving step, the magnetic head moves to a position where the reading element covers two bits, one bit having known magnetic information, the other bit being adjacent to the one bit and having unknown magnetic information. In the measuring step, the reading element measures magnetic field intensity coming from the recording medium. In the specifying step, magnetic information of the bit having the unknown magnetic information is specified based on the magnetic field intensity measured in the measuring step and magnetic information of the bit having the known magnetic information.
    Type: Grant
    Filed: September 10, 2009
    Date of Patent: September 20, 2011
    Assignee: TDK Corporation
    Inventors: Takumi Yanagisawa, Satoshi Miura
  • Patent number: 8018693
    Abstract: A magnetic detector includes a magnetoresistive element and an impact sensor. The magnetoresistive element has a plurality of element-constituent layers that are stacked and include a free layer having a magnetization direction that changes in response to a magnetic field to be detected by the magnetic detector. The impact sensor has a plurality of sensor-constituent layers that are made of materials the same as those of the element-constituent layers and stacked in the same order as the element-constituent layers. The plurality of sensor-constituent layers include an impact detecting layer corresponding to the free layer and having a magnetization direction that changes by an inverse magnetostrictive effect in response to distortion created in the impact detecting layer by an impact received by the magnetic detector. The impact detecting layer exhibits a greater amount of change in magnetization direction when the magnetic detector receives an impact, compared with the free layer.
    Type: Grant
    Filed: January 21, 2009
    Date of Patent: September 13, 2011
    Assignee: TDK Corporation
    Inventor: Takumi Yanagisawa
  • Publication number: 20110216432
    Abstract: A reading element of a magnetic head has a first magnetoresistive effect part (first MR part) and a second magnetoresistive effect part (second MR part), an electrical resistance of the first MR part changing according to an external magnetic field applied to a first magnetic field sense area, an electrical resistance of the second MR part changing according to an external magnetic field applied to a second magnetic field sense area. A width of the second magnetic field sense area in a track width direction of the recording medium is larger than a width of the first magnetic field sense area in the track width direction, and a phase of change in the electrical resistance of the second MR part with respect to the external magnetic field substantially reverses to or substantially the same as a phase in the electrical resistance of the first MR part.
    Type: Application
    Filed: March 5, 2010
    Publication date: September 8, 2011
    Applicant: TDK Corporation
    Inventor: Takumi YANAGISAWA