Patents by Inventor Yoh Iwasaki

Yoh Iwasaki 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: 10770264
    Abstract: An interference optical system unit includes at least one electromagnetic lens that forms an image of a charged particle beam, at least one charged particle beam biprism, and a support member for the electromagnetic lens and the charged particle beam biprism. The electromagnetic lens, the charged particle beam biprism, the support member, and a space to an image plane of the electromagnetic lens are integrally configured as one unit. The interference optical system unit is disposed to have an optical axis coaxialized with an optical axis of an imaging optical system of an upstream stage that is disposed on an upstream side of the unit in a flow direction of the charged particle beam. A focal length of the electromagnetic lens and a deflection angle of the charged particle beam given by the charged particle beam biprism are controlled to generate an interference fringe of the charged particle beam on the image plane of the electromagnetic lens.
    Type: Grant
    Filed: March 21, 2019
    Date of Patent: September 8, 2020
    Assignee: RIKEN
    Inventors: Yoh Iwasaki, Ken Harada, Keiko Shimada
  • Publication number: 20190295816
    Abstract: An interference optical system unit includes at least one electromagnetic lens that forms an image of a charged particle beam, at least one charged particle beam biprism, and a support member for the electromagnetic lens and the charged particle beam biprism. The electromagnetic lens, the charged particle beam biprism, the support member, and a space to an image plane of the electromagnetic lens are integrally configured as one unit. The interference optical system unit is disposed to have an optical axis coaxialized with an optical axis of an imaging optical system of an upstream stage that is disposed on an upstream side of the unit in a flow direction of the charged particle beam. A focal length of the electromagnetic lens and a deflection angle of the charged particle beam given by the charged particle beam biprism are controlled to generate an interference fringe of the charged particle beam on the image plane of the electromagnetic lens.
    Type: Application
    Filed: March 21, 2019
    Publication date: September 26, 2019
    Inventors: Yoh IWASAKI, Ken HARADA, Keiko SHIMADA
  • Patent number: 7147916
    Abstract: A magnetic material having a structure of a material having a ferromagnetic phase at ordinary temperature as a core and a material having an antiferromagnetic phase at ordinary temperature surrounding the periphery of the core in the form of a shell, wherein a ratio between a volume of the ferromagnetic phase material and the volume of the antiferromagnetic phase material in the magnetic material is in a range where no exchange biasing field of the magnetic material appears and a rotational hysteresis loss of the magnetic material is made the maximum, a method of producing the same, and a magnetic recording medium using the same.
    Type: Grant
    Filed: August 29, 2002
    Date of Patent: December 12, 2006
    Assignee: Sony Corporation
    Inventors: Yoh Iwasaki, Yuichi Sasaki, Mikihisa Mizuno
  • Publication number: 20060204789
    Abstract: A magnetic material having a structure of a material having a ferromagnetic phase at ordinary temperature as a core and a material having an antiferromagnetic phase at ordinary temperature surrounding the periphery of the core in the form of a shell, wherein a ratio between a volume of the ferromagnetic phase material and the volume of the antiferromagnetic phase material in the magnetic material is in a range where no exchange biasing field of the magnetic material appears and a rotational hysteresis loss of the magnetic material is made the maximum, a method of producing the same, and a magnetic recording medium using the same.
    Type: Application
    Filed: May 15, 2006
    Publication date: September 14, 2006
    Inventors: Yoh Iwasaki, Yuichi Sasaki, Mikihisa Mizuno
  • Publication number: 20040216810
    Abstract: A magnetic material having a structure of a material having a ferromagnetic phase at ordinary temperature as a core and a material having an antiferromagnetic phase at ordinary temperature surrounding the periphery of the core in the form of a shell, wherein a ratio between a volume of the ferromagnetic phase material and the volume of the antiferromagnetic phase material in the magnetic material is in a range where no exchange biasing field of the magnetic material appears and a rotational hysteresis loss of the magnetic material is made the maximum, a method of producing the same, and a magnetic recording medium using the same.
    Type: Application
    Filed: May 28, 2004
    Publication date: November 4, 2004
    Inventors: Yoh Iwasaki, Yuichi Sasaki, Mikihisa Mizuno
  • Patent number: 6773745
    Abstract: A method of producing a magnetic recording medium comprising the step of forming a magnetic layer on a non-magnetic base film running at a constant speed by continuous oblique evaporation depositing metal vapor of volatilized metal incident obliquely to a surface of the non-magnetic base film, wherein the evaporation is conducted at a film forming rate, defined as an average deposition rate of the magnetic layer at a part of the non-magnetic base film exposed to the incident metal vapor, of not less than a predetermined rate to form an internal microstructure of the magnetic layer comprising columns each having a diameter of not more than about 15 nm constituted by magnetic particles having a size of not more than about 10 nm connected in chains in a direction substantially perpendicular to the magnetic layer and non-magnetic particles packed between the columns and separating the columns from each other, and a magnetic recording medium produced by the above method.
    Type: Grant
    Filed: August 14, 2002
    Date of Patent: August 10, 2004
    Assignee: Sony Corporation
    Inventors: Yuichi Arisaka, Junichi Tachibana, Takuya Ito, Yoh Iwasaki
  • Patent number: 6625058
    Abstract: A method of modulating magnetic properties of a magnetic film, and new magnetic devices that utilizes the method are set forth. The method works in a multi-layer structure consisting of two layers of low electrical resistivity separated by a spacer layer with higher resistivity, wherein at least one of the layers is magnetic. The modulation of magnetic properties is executed by applying an external voltage to the multi-layer. An electric field induced in the multi-layer by the voltage changes electronic states near the interface between layers, which leads to a modification of either of the following magnetic properties: interface magnetic anisotropy, interface magnetostriction, or inter-layer magnetic coupling. The modulation of the magnetic properties thus performed deflects or rotates magnetization vector in the magnetic film, which is utilized in device applications.
    Type: Grant
    Filed: June 14, 2002
    Date of Patent: September 23, 2003
    Assignee: Sony Corporation
    Inventor: Yoh Iwasaki
  • Publication number: 20030068530
    Abstract: A magnetic material having a structure of a material having a ferromagnetic phase at ordinary temperature as a core and a material having an antiferromagnetic phase at ordinary temperature surrounding the periphery of the core in the form of a shell, wherein a ratio between a volume of the ferromagnetic phase material and the volume of the antiferromagnetic phase material in the magnetic material is in a range where no exchange biasing field of the magnetic material appears and a rotational hysteresis loss of the magnetic material is made the maximum, a method of producing the same, and a magnetic recording medium using the same.
    Type: Application
    Filed: August 29, 2002
    Publication date: April 10, 2003
    Inventors: Yoh Iwasaki, Yuichi Sasaki, Mikihisa Mizuno
  • Publication number: 20030054202
    Abstract: A method of producing a magnetic recording medium comprising the step of forming a magnetic layer on a non-magnetic base film running at a constant speed by continuous oblique evaporation depositing metal vapor of volatilized metal incident obliquely to a surface of the non-magnetic base film, wherein the evaporation is conducted at a film forming rate, defined as an average deposition rate of the magnetic layer at a part of the non-magnetic base film exposed to the incident metal vapor, of not less than a predetermined rate to form an internal microstructure of the magnetic layer comprising columns each having a diameter of not more than about 15 nm constituted by magnetic particles having a size of not more than about 10 nm connected in chains in a direction substantially perpendicular to the magnetic layer and non-magnetic particles packed between the columns and separating the columns from each other, and a magnetic recording medium produced by the above method.
    Type: Application
    Filed: August 14, 2002
    Publication date: March 20, 2003
    Inventors: Yuichi Arisaka, Junichi Tachibana, Takuya Ito, Yoh Iwasaki
  • Patent number: 6534203
    Abstract: A magnetic recording medium includes an anti-ferromagnetic layer 2 layered on at least one of the opposite major surfaces in a direction along the thickness of a ferromagnetic recording layer 3. It is possible for magnetization in the vicinity of a surface of an anti-ferromagnetic layer 2 facing a ferromagnetic recording layer 3 to be rotated simultaneously with rotation of magnetization of the ferromagnetic recording layer 3. It is also possible for the intensity of exchange coupling between the two layers to be larger than the total magnetic anisotropy of the anti-ferromagnetic layer 2. It is similarly possible for the intensity of the exchange coupling between the two layers to be smaller than the total magnetic anisotropy of the anti-ferromagnetic layer 2 and larger than the magnetic domain energy of the anti-ferromagnetic layer 2.
    Type: Grant
    Filed: March 25, 1999
    Date of Patent: March 18, 2003
    Assignee: Sony Corporation
    Inventors: Yoh Iwasaki, Minoru Ikarashi, Masafumi Takiguchi
  • Publication number: 20030012050
    Abstract: A new method of modulating magnetic properties of a magnetic film, and new magnetic devices that utilizes the method are disclosed. The method works in a multi-layer structure consisting of two layers of low electrical resistivity separated by a spacer layer with higher resistivity, wherein at least one of the layers is magnetic. The modulation of magnetic properties is executed by applying an external voltage to the multi-layer. An electric field induced in the multi-layer by the voltage changes electronic states near the interface between layers, which leads to a modification of either of the following magnetic properties: interface magnetic anisotropy, interface magnetostriction, or inter-layer magnetic coupling. The modulation of the magnetic properties thus performed deflects or rotates magnetization vector in the magnetic film, which is utilized in device applications.
    Type: Application
    Filed: June 14, 2002
    Publication date: January 16, 2003
    Inventor: Yoh Iwasaki
  • Patent number: 6483741
    Abstract: A magnetic functional device allowing magnetization switching at a high speed even if the size of a magnetic substance is made finer on the sub-micron order. The magnetic functional device includes an information carrier layer formed by a magnetic substance; and a strain-imparting layer (such as piezoelectric layer) formed below the information layer and operably configured to impart a drive force to change the direction of a magnetization vector lying in a first plane of the information carrier thereby processing binary or more information by magnetization directions of the information carrier layer; wherein the drive force is applied in pulse to the information carrier layer in a direction nearly perpendicular to the first plane in which lies the magnetization vector of the information carrier layer when the magnetization vector is in an initial state before the application of the drive force. An effective field derived from a magnetic anisotropy or exchange interaction is used as the drive force.
    Type: Grant
    Filed: September 18, 2000
    Date of Patent: November 19, 2002
    Assignee: Sony Corporation
    Inventors: Yoh Iwasaki, Teiichi Miyauchi, Kazuhiro Bessho
  • Patent number: 6480412
    Abstract: A potential barrier region is positioned in direct or indirect contact with a region containing a magnetic element. The region containing a magnetic body has a multi-layered structure in which two ferromagnetic layers are separated by a non-magnetic intermediate layer, for example. The potential barrier region may be composed of a metal layer and a semiconductor layer, for example, and a Schottky barrier is produced between them. Magnetization of the region containing a magnetic body is controlled by modulating the potential barrier of the potential barrier region by means of application of an electric field. By using at least one magnetization of the region containing a magnetic element, storage of information is effected.
    Type: Grant
    Filed: October 26, 2000
    Date of Patent: November 12, 2002
    Assignee: Sony Corporation
    Inventors: Kazuhiro Bessho, Yoh Iwasaki
  • Patent number: 6387476
    Abstract: A magnetic functional element can operate stably and reliably with a satisfactorily low rate of power consumption if used to realize an enhanced degree of integration. The magnetic fuctional element comprises strain-sensitive magnetic layer 2 having a magnetic state variable with strain and a strain applying layer 3 adapted to apply strain to the strain-sensitive magnetic layer. The magnetic state of the strain-sensitive magnetic layer 2 is controlled by controlling the strain applied to the strain-sensitive magnetic layer 2. Thus, it is no longer necessary to generate a magnetic field by means of an electric current in order to change the magnetic state of the element.
    Type: Grant
    Filed: September 10, 1999
    Date of Patent: May 14, 2002
    Assignee: Sony Corporation
    Inventors: Yoh Iwasaki, Kazuhiro Bessho
  • Publication number: 20010051288
    Abstract: A magnetic recording medium includes an anti-ferromagnetic layer 2 layered on at least one of the opposite major surfaces in a direction along the thickness of a ferromagnetic recording layer 3. It is possible for magnetization in the vicinity of a surface of an anti-ferromagnetic layer 2 facing a ferromagnetic recording layer 3 to be rotated simultaneously with rotation of magnetization of the ferromagnetic recording layer 3. It is also possible for the intensity of exchange coupling between the two layers to be larger than the total magnetic anisotropy of the anti-ferromagnetic layer 2. It is similarly possible for the intensity of the exchange coupling between the two layers to be smaller than the total magnetic anisotropy of the anti-ferromagnetic layer 2 and larger than the magnetic domain energy of the anti-ferromagnetic layer 2.
    Type: Application
    Filed: March 25, 1999
    Publication date: December 13, 2001
    Inventors: YOH IWASAKI, MINORU IKARASHI, MASAFUMI TAKIGUCHI
  • Patent number: 6178112
    Abstract: An element that is able to control magnetization without applying a magnetic field from outside. A magnetized area formed of a ferromagnetic material is split by a spacer area of a composite material including a magnetic material and a semiconductor material. A stimulus is applied from outside to the spacer area to change the magnetic interaction between split magnetized areas to control the magnetization of the magnetized areas. Alternatively, a layered assembly made up of an electrically conductive layer containing an electrically conductive material and plural magnetic layers is provided so that the electrically conductive layer is arranged between the magnetic layers. The current is caused to flow through the electrically conductive layer to change the magnetic coupling state between the magnetic layers to control the direction of magnetization between the magnetic layers.
    Type: Grant
    Filed: February 12, 1999
    Date of Patent: January 23, 2001
    Assignee: Sony Corporation
    Inventors: Kazuhiro Bessho, Yoh Iwasaki
  • Patent number: 5589283
    Abstract: A soft magnetic thin film is fabricated by depositing metallic particles obliquely on a substrate. The sign and magnitude of the crystalline magnetic anisotropy of the soft magnetic thin film are selected to cancel out the shape magnetic anisotropy depending on an inclined columnar crystalline structure and the stress-induced magnetic anisotropy. The soft magnetic thin film has a reduced total magnetic anisotropy. A magnetic head incorporating the soft magnetic thin film has good recording and reproducing characteristics and high saturation magnetic characteristics.
    Type: Grant
    Filed: November 3, 1994
    Date of Patent: December 31, 1996
    Assignee: Sony Corporation
    Inventors: Yoh Iwasaki, Yosuke Murakami, Masao Itabashi