Patents by Inventor Kikuo Kusukawa

Kikuo Kusukawa 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: 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: 8917481
    Abstract: Provided are a structure of a high frequency magnetic field assisted magnetic recording head in which the positional relationship of a main magnetic pole and a spin torque oscillator in a cross-track direction is accurately determined, and in which variations are not caused in high frequency magnetic field assist characteristics, and a method of manufacturing the structure. The high frequency magnetic field assisted magnetic recording head includes a main magnetic pole, a spin torque oscillator disposed on the main magnetic pole, and an insulating side gap covering a side surface of the main magnetic pole and a side surface of the spin torque oscillator. The main magnetic pole and the spin torque oscillator are formed between both side surfaces of the side gap. Thus, a self-alignment structure of the high frequency magnetic field assisted magnetic recording head is obtained.
    Type: Grant
    Filed: April 17, 2014
    Date of Patent: December 23, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Kikuo Kusukawa, Junichiro Shimizu, Katsuro Watanabe
  • Publication number: 20140313616
    Abstract: Provided are a structure of a high frequency magnetic field assisted magnetic recording head in which the positional relationship of a main magnetic pole and a spin torque oscillator in a cross-track direction is accurately determined, and in which variations are not caused in high frequency magnetic field assist characteristics, and a method of manufacturing the structure. The high frequency magnetic field assisted magnetic recording head includes a main magnetic pole, a spin torque oscillator disposed on the main magnetic pole, and an insulating side gap covering a side surface of the main magnetic pole and a side surface of the spin torque oscillator. The main magnetic pole and the spin torque oscillator are formed between both side surfaces of the side gap. Thus, a self-alignment structure of the high frequency magnetic field assisted magnetic recording head is obtained.
    Type: Application
    Filed: April 17, 2014
    Publication date: October 23, 2014
    Applicant: Hitachi, Ltd.
    Inventors: Kikuo KUSUKAWA, Junichiro SHIMIZU, Katsuro WATANABE
  • Publication number: 20140063658
    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: Application
    Filed: August 16, 2013
    Publication date: March 6, 2014
    Applicant: HITACHI, LTD.
    Inventors: Junichiro SHIMIZU, Kikuo KUSUKAWA, Yo SATO, Masukazu IGARASHI
  • Patent number: 8472135
    Abstract: According to one embodiment, a high-frequency magnetic field-assisted magnetic recording head includes a main pole adapted for producing a writing magnetic field, a STO positioned above the main pole, a low-resistance layer positioned above the STO, and a current confinement layer positioned between the low-resistance layer and the main pole, wherein the main pole and the low-resistance layer are adapted for acting as poles for writing data to a magnetic medium in response to a flow of current to the STO positioned therebetween to generate a high-frequency magnetic field which overlaps with the writing magnetic field, and wherein the current confinement layer is adapted for controlling a current density and/or a current density distribution of the current flowing to the STO. Other magnetic recording heads and methods of production thereof are also described according to more embodiments.
    Type: Grant
    Filed: March 9, 2012
    Date of Patent: June 25, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Kikuo Kusukawa, Masato Shiimoto, Kazuhiko Hosomi, Katsuro Watanabe
  • Patent number: 8351153
    Abstract: According to one embodiment, a magnetic recording head includes a main pole having a throat height portion and a flare portion that is connected to the throat height portion, the flare portion gradually being expanded in width to an upper part in an element height direction. The head also includes a sub pole, magnetic shields disposed via a nonmagnetic layer on a trailing side of the main pole and on both sides in a track width direction of the main pole, and a coil for generating a recording magnetic field from the main pole. The nonmagnetic layer has an upper portion of which the thickness is increased stepwise or in a tapered manner in the element height direction with respect to an ABS side, and each portion of the magnetic shields adjacent to the main pole has a shape corresponding to a surface shape of the nonmagnetic layer.
    Type: Grant
    Filed: September 14, 2009
    Date of Patent: January 8, 2013
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Isao Nunokawa, Mikito Sugiyama, Kikuo Kusukawa, Hiroyuki Hoshiya
  • Patent number: 8335051
    Abstract: A recording head having a narrowed track has a high recording magnetic field strength and a high recording magnetic field gradient has certain problems which may be difficult to overcome. In one embodiment, a magnetic film, which overhangs from a track width, is provided on a trailing side of a. region retracted from an ABS of a main pole facing a recording medium. Thereby, a magnetic field strength on the trailing side is increased so that a difference in distribution of magnetic field strength defined by a geometrical bevel angle given to the main pole is increased. Consequently, writing performance of the main pole is improved while forming a large magnetic clearance angle with respect to an adjacent track and suppresses writing into an adjacent track when skew occurs. Other systems and methods are also disclosed regarding a head with a high recording magnetic field using an overhanging magnetic film.
    Type: Grant
    Filed: December 11, 2009
    Date of Patent: December 18, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Isao Nunokawa, Mikito Sugiyama, Kikuo Kusukawa, Kimitoshi Etoh
  • Patent number: 8107193
    Abstract: According to one embodiment, a perpendicular magnetic recording head includes a main magnetic pole including a write magnetic pole layer for recording, the write magnetic pole layer comprising magnetic layers being antiferromagnetically coupled via a thin non-magnetic conductor layer between the magnetic layers, wherein the write magnetic pole layer for recording has a flare section which gradually widens in a height-wise direction of a throat height section. The main magnetic pole also includes a non-magnetic cap layer laminated above an uppermost layer of the write magnetic pole layer, the non-magnetic cap layer being textured to provide anisotropy, and a subsidiary magnetic pole layer for supplementing the recording laminated above the non-magnetic cap layer. The head also includes an auxiliary magnetic pole, a magnetic shield positioned via a non-magnetic layer on a trailing edge and both sides of the main magnetic pole in a track width direction, and a coil for generating a recording magnetic field.
    Type: Grant
    Filed: April 8, 2010
    Date of Patent: January 31, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Isao Nunokawa, Mikito Sugiyama, Kikuo Kusukawa, Keizo Kato
  • Publication number: 20110249360
    Abstract: According to one embodiment, a perpendicular magnetic recording head includes a main magnetic pole including a write magnetic pole layer for recording, the write magnetic pole layer comprising magnetic layers being antiferromagnetically coupled via a thin non-magnetic conductor layer between the magnetic layers, wherein the write magnetic pole layer for recording has a flare section which gradually widens in a height-wise direction of a throat height section. The main magnetic pole also includes a non-magnetic cap layer laminated above an uppermost layer of the write magnetic pole layer, the non-magnetic cap layer being textured to provide anisotropy, and a subsidiary magnetic pole layer for supplementing the recording laminated above the non-magnetic cap layer. The head also includes an auxiliary magnetic pole, a magnetic shield positioned via a non-magnetic layer on a trailing edge and both sides of the main magnetic pole in a track width direction, and a coil for generating a recording magnetic field.
    Type: Application
    Filed: April 8, 2010
    Publication date: October 13, 2011
    Inventors: Isao Nunokawa, Mikito Sugiyama, Kikuo Kusukawa, Keizo Kato
  • Patent number: 7895732
    Abstract: An embodiment of the present invention relates to a method of manufacturing a perpendicular magnetic recording having a main pole, return pole and trailing side shield disposed on the trailing side and the cross track direction side of said main pole. A process is described where the main pole has an etching layer in the upper part. The top and sides of the main pole having the etching signal layer in the upper part are covered with a nonmagnetic gap layer while leaving open a region forming the side shield. The nonmagnetic gap layer is then etched until a signal from the etching signal layer is detected by an etching signal detector. The trailing side shield on the top and sides of the nonmagnetic gap layer are then formed after the etching is halted.
    Type: Grant
    Filed: March 15, 2007
    Date of Patent: March 1, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Tomohiro Okada, Isao Nunokawa, Kimitoshi Etoh, Kikuo Kusukawa
  • Publication number: 20100149697
    Abstract: A recording head having a narrowed track has a high recording magnetic field strength and a high recording magnetic field gradient has certain problems which may be difficult to overcome. In one embodiment, a magnetic film, which overhangs from a track width, is provided on a trailing side of a region retracted from an ABS of a main pole facing a recording medium. Thereby, a magnetic field strength on the trailing side is increased so that a difference in distribution of magnetic field strength defined by a geometrical Bevel angle given to the main pole is increased. Consequently, writing performance of the main pole is improved while forming a large magnetic clearance angle with respect to an adjacent track and suppresses writing into an adjacent track when skew occurs. Other systems and methods are also disclosed regarding a head with a high recording magnetic field using an overhanging magnetic film.
    Type: Application
    Filed: December 11, 2009
    Publication date: June 17, 2010
    Inventors: Isao Nunokawa, Mikito Sugiyama, Kikuo Kusukawa, Kimitoshi Etoh
  • Patent number: 7710685
    Abstract: If the length of a track-defining section from an air bearing surface varies due to tolerance during a head manufacturing process, the recording magnetic field changes, which involves the variation of the track width to be recorded on the medium. In accordance with an embodiment of the present invention, the main magnetic pole of a magnetic head includes a track-defining section shaped in trapezoid and a magnetic flux guiding section formed in trapezoid, as viewed from above. The track-defining section is formed such that its width parallel to the air bearing surface (ABS) increases at the rate of 10 to 20% with respect to its height-direction length. The rate of 10 to 20% is a range in which the shape is properly controllable taking into account the variations resulting from the tolerance of the head manufacturing process.
    Type: Grant
    Filed: January 5, 2007
    Date of Patent: May 4, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hisashi Kimura, Atsushi Kato, Norihiro Ookawa, Kikuo Kusukawa
  • Publication number: 20100091413
    Abstract: According to one embodiment, a magnetic recording head includes a main pole having a throat height portion and a flare portion that is connected to the throat height portion, the flare portion gradually being expanded in width to an upper part in an element height direction. The head also includes a sub pole, magnetic shields disposed via a nonmagnetic layer on a trailing side of the main pole and on both sides in a track width direction of the main pole, and a coil for generating a recording magnetic field from the main pole. The nonmagnetic layer has an upper portion of which the thickness is increased stepwise or in a tapered manner in the element height direction with respect to an ABS side, and each portion of the magnetic shields adjacent to the main pole has a shape corresponding to a surface shape of the nonmagnetic layer.
    Type: Application
    Filed: September 14, 2009
    Publication date: April 15, 2010
    Inventors: Isao Nunokawa, Mikito Sugiyama, Kikuo Kusukawa, Hiroyuki Hoshiya
  • Publication number: 20090154021
    Abstract: Embodiments of the present invention provide a magnetic head that can stably supply a perpendicular magnetic field component while generating high recording field strength from a main pole. According to one embodiment, a magnetic body is deposited in a trailing side of a pole tip of a main pole via a nonmagnetic layer, so that a second flare section is magnetically coupled with each sidewall.
    Type: Application
    Filed: November 20, 2008
    Publication date: June 18, 2009
    Inventors: Isao Nunokawa, Mikito Sugiyama, Kikuo Kusukawa, Hiroyuki Hoshiya
  • Patent number: 7389578
    Abstract: Embodiments in accordance with the present invention relate to methods wherein when a main pole is processed by using an ion milling technique, a re-adhesion layer created on the side face of the resist mask is removed with certainty. In one embodiment, an inorganic insulator from 5 nm to 100 nm which is soluble in an alkaline is arranged between the main pole material and a mask for processing the main pole material, and the main pole is processed by ion milling. After this process, the mask is peeled off, a surface treatment is performed by using an alkaline solution, resulting in the re-deposition film being removed.
    Type: Grant
    Filed: December 21, 2006
    Date of Patent: June 24, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kimitoshi Etoh, Kikuo Kusukawa, Hisashi Kimura, Tomohiro Okada
  • Patent number: 7280321
    Abstract: A magnetoresistive head of a type including a magnetoresistive film arranged between a lower shield layer and an upper shield layer, wherein the lower shield layer has a non-magnetic layer adjacent to it and the lower shield layer and the upper shield layer are formed such that their separation at at least part of a boundary between the lower shield layer and the upper shield layer is larger than their separation in a vicinity of the magnetoresistive film, and an insulating film is arranged between the lower shield layer and the upper shield layer, wherein the lower shield layer and the non-magnetic layer adjacent thereto are formed such that they differ in height and there exists a difference in level at their boundary.
    Type: Grant
    Filed: August 10, 2006
    Date of Patent: October 9, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Katsuro Watanabe, Kikuo Kusukawa, Kenichi Meguro
  • Patent number: 7274542
    Abstract: A magnetic sensor includes a spacer having at least a nonmagnetic metal layer inserted between the upper shield layer and the longitudinal bias layers or between the upper shield layer and the longitudinal bias layers plus the magnetoresistive film, the shortest distance between the longitudinal bias layers and the free layer of the magnetoresistive film is set smaller than the shortest distance between the longitudinal bias layers and the upper shield layer, and this arrangement ensures that the amount of magnetic flux entering the magnetoresistive film from the longitudinal bias layers is larger than that absorbed by the upper shield layer, thus realizing a magnetic sensor whose Barkhausen noise is suppressed.
    Type: Grant
    Filed: February 5, 2003
    Date of Patent: September 25, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Taku Shintani, Katsuro Watanabe, Masahiko Hatatani, Kikuo Kusukawa
  • Publication number: 20070217069
    Abstract: Embodiments in accordance with the present invention provide a trailing side shield around a main pole and control the gap length on its trailing side to high accuracy so as to increase a recording magnetic field gradient. An etching signal layer is provided on a main pole, and the gap length on the trailing side of the main pole is controlled to high accuracy by stopping ion milling when a signal from this layer is detected.
    Type: Application
    Filed: March 15, 2007
    Publication date: September 20, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Tomohiro Okada, Isao Nunokawa, Kimitoshi Etoh, Kikuo Kusukawa
  • Publication number: 20070195454
    Abstract: If the length of a track-defining section from an air bearing surface varies due to tolerance during a head manufacturing process, the recording magnetic field changes, which involves the variation of the track width to be recorded on the medium. In accordance with an embodiment of the present invention, the main magnetic pole of a magnetic head includes a track-defining section shaped in trapezoid and a magnetic flux guiding section formed in trapezoid, as viewed from above. The track-defining section is formed such that its width parallel to the air bearing surface (ABS) increases at the rate of 10 to 20% with respect to its height-direction length. The rate of 10 to 20% is a range in which the shape is properly controllable taking into account the variations resulting from the tolerance of the head manufacturing process.
    Type: Application
    Filed: January 5, 2007
    Publication date: August 23, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hisashi Kimura, Atsushi Kato, Norihiro Ookawa, Kikuo Kusukawa
  • Publication number: 20070186409
    Abstract: Embodiments in accordance with the present invention relate to methods wherein when a main pole is processed by using an ion milling technique, a re-adhesion layer created on the side face of the resist mask is removed with certainty. In one embodiment, an inorganic insulator from 5 nm to 100 nm which is soluble in an alkaline is arranged between the main pole material and a mask for processing the main pole material, and the main pole is processed by ion milling. After this process, the mask is peeled off, a surface treatment is performed by using an alkaline solution, resulting in the re-deposition film being removed.
    Type: Application
    Filed: December 21, 2006
    Publication date: August 16, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kimitoshi Etoh, Kikuo Kusukawa, Hisashi Kimura, Tomohiro Okada