Patents by Inventor Yoshiaki Kawato

Yoshiaki Kawato 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: 7057853
    Abstract: The disclosed invention provides a magnetic head of high stability in which “erase after write” is prevented. Here is provided a magnetic head comprising a thin-film magnetic head for perpendicular magnetic recording, the thin-film magnetic head including a main pole with its tip facing a magnetic recording medium and coils for exciting the main pole, wherein the tip of or at least a part of the main pole consists of a soft magnetic multilayer containing laminations, each of which comprises a first ferromagnetic film, a second ferromagnetic film, and an antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film, wherein the antiparallel coupling layer causes antiferromagnetic interlayer coupling of the first ferromagnetic film and the second ferromagnetic film.
    Type: Grant
    Filed: July 2, 2003
    Date of Patent: June 6, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yasuyuki Okada, Hiroyuki Hoshiya, Yoshiaki Kawato
  • Patent number: 7054106
    Abstract: Disclosed herein is a magnetic head for perpendicular recording in which the main magnetic pole has reduced remanent magnetization and is less liable to cause erasure after recording. These characteristic properties were realized by constructing the magnetic head such that the recording magnetic pole and the yoke are separate from each other and the main magnetic pole is formed from a material with a high saturation magnetic flux density and the yoke is formed from a material having a negative magnetostriction constant.
    Type: Grant
    Filed: January 31, 2003
    Date of Patent: May 30, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Kazue Kudo, Yoshiaki Kawato, Kazuhiro Nakamoto, Nobuo Yoshida, Kimitoshi Etoh
  • Patent number: 7038881
    Abstract: The invention provides a magnetic head for perpendicular recording capable of recording with high linear recording density and high track density, and a magnetic disk drive incorporating the same. In order to achieve this, one or more sides of the main pole of the magnetic head for perpendicular recording except for the trailing side are formed in a taper with an appropriate angle against the tip surface of the main pole, and the yoke whose widest principal plane is in parallel to the tip surface is provided on the bottom of the main pole. Thereby, the invention achieves the magnetic head for perpendicular recording that generates a sufficiently high magnetic field, and assumes a sharp gradient of magnetic field on the trailing side. By incorporating this magnetic head, a magnetic disk drive capable of handling high linear recording density can be produced.
    Type: Grant
    Filed: August 27, 2003
    Date of Patent: May 2, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Kenchi Ito, Yoshiaki Kawato, Masafumi Mochizuki
  • Patent number: 6995949
    Abstract: A magnetic head includes a main pole having a first portion with a length (W1) in a cross-track direction which continuously increases from a leading edge side to a trailing edge side, a second portion formed on a trailing edge side of the first portion, and a third portion formed on a trailing edge side of the second portion. A length (W2) in the cross-track direction of a boundary line between the second portion and the third portion is longer than W1, and a length (W3) in the cross-track direction of a trailing edge of a third portion is substantially equal to W2.
    Type: Grant
    Filed: April 28, 2005
    Date of Patent: February 7, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Publication number: 20050214587
    Abstract: An improved perpendicular magnetic recording medium and an improved magnetic storage apparatus are provided, which are suitable for high speed and high density magnetic recording. A magnetic under layer of a two-layered perpendicular magnetic recording medium includes three layers: a ferromagnetic layer; a non-magnetic layer; and a ferromagnetic layer, wherein the ferromagnetic layers are antiferromagnetically coupled with each other, thereby preventing a magnetic flux from a magnetic wall in a magnetic under layer from entering a read back head.
    Type: Application
    Filed: April 12, 2005
    Publication date: September 29, 2005
    Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
  • Publication number: 20050185335
    Abstract: A magnetic head includes a main pole having a first portion with a length (W1) in a cross-track direction which continuously increases from a leading edge side to a trailing edge side, a second portion formed on a trailing edge side of the first portion, and a third portion formed on a trailing edge side of the second portion. A length (W2) in the cross-track direction of a boundary line between the second portion and the third portion is longer than W1, and a length (W3) in the cross-track direction of a trailing edge of a third portion is substantially equal to W2.
    Type: Application
    Filed: April 28, 2005
    Publication date: August 25, 2005
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Patent number: 6934128
    Abstract: Provided is a thin film single pole head for perpendicular magnetic recording, which has a structure offering a high formatted volume, easy servo, difficulty of influencing a recording pattern on a medium, and capability of shortening processing time. This thin film single pole head for perpendicular magnetic recording is formed on a reproducing head composed of a pair of shield layers formed on a substrate, and a reproducing element formed therebetween. A structure is provided, where an auxiliary pole is not disposed between the reproducing element of the reproducing head and the main pole of a recording head when seen from a surface facing to recording media.
    Type: Grant
    Filed: August 12, 2004
    Date of Patent: August 23, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Yuko Tsuchiya, Hiroyuki Hoshiya, Yoshiaki Kawato, Katsuro Watanabe, Hiroshi Ide
  • Patent number: 6926974
    Abstract: An improved perpendicular magnetic recording medium and an improved magnetic storage apparatus are provided, which are suitable for high speed and high density magnetic recording. A magnetic under layer of a two-layered perpendicular magnetic recording medium includes three layers: a ferromagnetic layer; a non-magnetic layer; and a ferromagnetic layer, wherein the ferromagnetic layers are antiferromagnetically coupled with each other, thereby preventing a magnetic flux from a magnetic wall in a magnetic under layer from entering a read back head.
    Type: Grant
    Filed: May 22, 2001
    Date of Patent: August 9, 2005
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Masaaki Futamoto, Kazuhiro Nakamoto
  • Publication number: 20050163962
    Abstract: A perpendicular magnetic recording medium for thermo-magnetic printing has an ultra-high recording density and is resistant to thermal decay of magnetization. An intermediate layer of the medium is provided between a first recording layer using a low-noise Co alloy ferromagnetic substance and a second recording layer using a ferrimagnetic substance (e.g., a rare-earth element-transition metal compound) having a compensation temperature below an operation ambient temperature. A magnetic field is applied thereto to form a magnetization pattern on the first recording layer. It is then heated-up to be printed onto the second recording layer, which has a higher coercivity at the ambient temperature, and a recording field is suitably set to form a magnetization pattern only on the first recording layer. The magnetization pattern is printed from the first recording layer to the second recording layer.
    Type: Application
    Filed: July 20, 2004
    Publication date: July 28, 2005
    Inventors: Yoshiaki Kawato, Kenchi Ito
  • Patent number: 6906898
    Abstract: An object of the present invention is to produce a differential detection read sensor for perpendicular magnetic recording using two magnetic resistance elements; and to provide a thin film head for perpendicular recording using the read sensor and a magnetic recording apparatus having high recording density equipped with the head. The object of the present invention can be achieved by a reproducing sensor comprising a pair of magnetic resistance layers; a non-magnetic conductive layer; a pair of conductive layers; and a pair of magnetic shields.
    Type: Grant
    Filed: October 1, 2003
    Date of Patent: June 14, 2005
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventor: Yoshiaki Kawato
  • Patent number: 6891697
    Abstract: A magnetic head having at least a main pole having a profile on a magnetic head air bearing surface composed of a first portion having a length in a cross-track direction which continuously increases from a leading edge to a trailing edge, and a second portion located on the side of the trailing edge of the first portion. A length of the second portion in the cross-track direction at the trailing edge is substantially equal to a length in the cross-track direction at the point of contact between the first and second portions. A rate of change in the length of the second portion in the cross-track direction from the leading edge to the trailing edge is different from a rate of increase in the length of the first portion in the cross-track direction.
    Type: Grant
    Filed: October 28, 2004
    Date of Patent: May 10, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Publication number: 20050057853
    Abstract: A magnetic head having at least a main pole having a profile on a magnetic head air bearing surface composed of a first portion having a length in a cross-track direction which continuously increases from a leading edge to a trailing edge, and a second portion located on the side of the trailing edge of the first portion. A length of the second portion in the cross-track direction at the trailing edge is substantially equal to a length in the cross-track direction at the point of contact between the first and second portions. A rate of change in the length of the second portion in the cross-track direction from the leading edge to the trailing edge is different from a rate of increase in the length of the first portion in the cross-track direction.
    Type: Application
    Filed: October 28, 2004
    Publication date: March 17, 2005
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Publication number: 20050018346
    Abstract: A method of fabricating a thin film magnetic recording head including a perpendicular recording head having an auxiliary pole, a main pole and a shield against an external magnetic field. The shield against the external magnetic field is formed so that an edge of the shield against the external magnetic field is disposed at a position recessed at least from an edge of the main pole relative to a surface against a medium.
    Type: Application
    Filed: August 25, 2004
    Publication date: January 27, 2005
    Inventors: Tomohiro Okada, Yoshiaki Kawato, Kaori Suzuki, Hiroshi Fukui, Isao Nunokawa
  • Publication number: 20050013058
    Abstract: Provided is a thin film single pole head for perpendicular magnetic recording, which has a structure offering a high formatted volume, easy servo, difficulty of influencing a recording pattern on a medium, and capability of shortening processing time. This thin film single pole head for perpendicular magnetic recording is formed on a reproducing head composed of a pair of shield layers formed on a substrate, and a reproducing element formed therebetween. A structure is provided, where an auxiliary pole is not disposed between the reproducing element of the reproducing head and the main pole of a recording head when seen from a surface facing to recording media.
    Type: Application
    Filed: August 12, 2004
    Publication date: January 20, 2005
    Inventors: Yuko Tsuchiya, Hiroyuki Hoshiya, Yoshiaki Kawato, Katsuro Watanabe, Hiroshi Ide
  • Patent number: 6813116
    Abstract: A single-pole type magnetic head for perpendicular recording which reduces the amount of side writing even in the presence of a yaw angle and prevents the effective track width from decreasing, and a magnetic recording disk apparatus using the same. A main pole is composed of at least two portions where the width of the first portion continuously increases from the upstream side to the downstream side in the medium moving direction and the width of the second portion is the same as the width of the first portion's downstream edge in the medium moving direction and is constant from the upstream side to the downstream side in the medium moving direction. This prevents the recording magnetic field strength from decreasing at the track edge and increases the effective track width while suppressing side writing, thereby realizing a magnetic recording disk apparatus with a high track density.
    Type: Grant
    Filed: December 9, 2002
    Date of Patent: November 2, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Atsushi Nakamura, Masafumi Mochizuki, Tomohiro Okada, Kimitoshi Etoh, Isao Nunokawa, Yoshiaki Kawato
  • Patent number: 6795277
    Abstract: Provided is a thin film single pole head for perpendicular magnetic recording, which has a structure offering a high formatted volume, easy servo, difficulty of influencing a recording pattern on a medium, and capability of shortening processing time. This thin film single pole head for perpendicular magnetic recording is formed on a reproducing head composed of a pair of shield layers formed on a substrate, and a reproducing element formed therebetween. A structure is provided, where an auxiliary pole is not disposed between the reproducing element of the reproducing head and the main pole of a recording head when seen from a surface facing to recording media.
    Type: Grant
    Filed: February 8, 2002
    Date of Patent: September 21, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Yuko Tsuchiya, Hiroyuki Hoshiya, Yoshiaki Kawato, Katsuro Watanabe, Hiroshi Ide
  • Patent number: 6785097
    Abstract: The invention fabricates a perpendicular recording head eliminating influence of external magnetic field and provides a magnetic disk drive having high stability by using the magnetic recording head and constructs a structure in which shield against external magnetic field is formed from a main pole via a gap layer and an edge portion thereof is recessed from a surface against a medium. By providing the shield against the external magnetic field, the influence of the external magnetic field is restrained and by recessing the edge from the surface against the medium, leakage of magnetic field from the shield against the external magnetic field to the medium is prevented to thereby prevent a magnetization signal from being erased.
    Type: Grant
    Filed: February 11, 2002
    Date of Patent: August 31, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Tomohiro Okada, Yoshiaki Kawato, Kaori Suzuki, Hiroshi Fukui, Isao Nunokawa
  • Publication number: 20040150912
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field exceeding 10 kOe (oersted), while also modified to suppress remanent magnetic fields occurring immediately after writing operation. In a perpendicular magnetic head comprising a main pole, a return path for supplying a magnetic flux to that main pole, and an conductive coil for excitation of the main pole and return path, the main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer, the low saturation flux density layer has a thickness within 0.5 to 5 nanometers, the high saturation flux density layer has a thickness from 10 to 50 nanometers for suppressing remanent magnetization and preventing erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Application
    Filed: August 20, 2003
    Publication date: August 5, 2004
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20040150910
    Abstract: A magnetic head for perpendicular recording without writing from the lateral sides of a mains pole and without erasing data on adjacent tracks. A magnetic disk storage apparatus using the magnetic head. The lateral side of the main pole of a magnetic head for perpendicular recording may have an inverted tapered shape obtained by forming a groove as a track portion to an inorganic insulating layer and then forming a magnetic layer and then flattening the upper surface. A leading edge, a trailing edge, or both lateral edges of the magnetic head may be tapered. The taper may be either smooth and linear or curved in profile.
    Type: Application
    Filed: February 2, 2004
    Publication date: August 5, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Tomohiro Okada, Yoshiaki Kawato, Yasutaka Nishida, Yasuo Wakaki, Masafumi Mochizuki, Hisashi Takano
  • Publication number: 20040120074
    Abstract: The disclosed invention provides a magnetic head of high stability in which “erase after write” is prevented. Here is provided a magnetic head comprising a thin-film magnetic head for perpendicular magnetic recording, the thin-film magnetic head including a main pole with its tip facing a magnetic recording medium and coils for exciting the main pole, wherein the tip of or at least a part of the main pole consists of a soft magnetic multilayer containing laminations, each of which comprises a first ferromagnetic film, a second ferromagnetic film, and an antiparallel coupling layer formed between the first ferromagnetic film and the second ferromagnetic film, wherein the antiparallel coupling layer causes antiferromagnetic interlayer coupling of the first ferromagnetic film and the second ferromagnetic film.
    Type: Application
    Filed: July 2, 2003
    Publication date: June 24, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Yasuyuki Okada, Hiroyuki Hoshiya, Yoshiaki Kawato