Patents by Inventor Akihiro Odagawa

Akihiro Odagawa 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).

  • Publication number: 20060273877
    Abstract: The present invention provides a variable-resistance element in which deterioration in its capacity for resistance variation is suppressed, even when heat treatment is conducted in a reducing atmosphere, and a non-volatile memory using the same. Specifically, the present invention provides (1) a variable-resistance element provided with a material layer comprising an oxide semiconductor having a perovskite structure represented by the chemical formula RMCoO3 (wherein R is a rare-earth element and M is an alkaline-earth element) and first and second electrodes electrically connecting to the material layer, the resistance of the material layer being variable in accordance with an electric current or voltage applied across the first and second electrodes, and (2) a non-volatile memory comprising a transistor and the variable-resistance element, the transistor and the variable-resistance element being electrically connected.
    Type: Application
    Filed: May 4, 2006
    Publication date: December 7, 2006
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Tsutomu Kanno, Akihiro Odagawa, Yasunari Sugita, Akihiro Sakai, Hideaki Adachi
  • Patent number: 7079361
    Abstract: The present invention provides a magnetoresistive (MR) element that is excellent in MR ratio and thermal stability and includes at least one magnetic layer including a ferromagnetic material M-X expressed by M100-aXa. Here, M is at least one selected from Fe, Co and Ni, X is expressed by X1bX2cX3d (X1 is at least one selected from Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt and Au, X2 is at least one selected from Al, Sc, Ti, V, Cr, Mn, Ga, Ge, Y, Zr, Nb, Mo, Hf, Ta, W, Re, Zn and lanthanide series elements, and X3 is at least one selected from Si, B, C, N, O, P and S), and a, b, c and d satisfy 0.05?a?60, 0?b?60, 0?c?30, 0?d?20, and a=b+c+d.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: July 18, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasunari Sugita, Masayoshi Hiramoto, Nozomu Matsukawa, Mitsuo Satomi, Yoshio Kawashima, Akihiro Odagawa
  • Patent number: 7067205
    Abstract: A thermoelectric transducing material according to this invention includes a layered cobaltite based substance represented by the chemical formula AxCoO2, wherein A consists of an element or element group selected from alkali metal elements and alkali earth group elements and is compositionally modulated in a thickness-wise direction of layers in a structure of the layered cobaltite based substance.
    Type: Grant
    Filed: December 9, 2003
    Date of Patent: June 27, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hideaki Adachi, Akihiro Odagawa
  • Publication number: 20060120205
    Abstract: An electro-resistance element that has a different configuration from conventional elements and shows outstanding resistance change characteristics is provided. An electro-resistance element has two or more states in which electric resistance values are different, and is switchable from one of the two or more states into another by application of a predetermined voltage or current. The electro-resistance element includes: a multilayer structure including an upper electrode, a lower electrode, and an electro-resistance layer sandwiched by the electrodes, the multilayer structure disposed on a substrate; wherein the electro-resistance layer has a spinel structure, and a surface of the lower electrode that faces the electro-resistance layer is oxidized. The electro-resistance element can be manufactured by a manufacturing process at 400° C. or lower.
    Type: Application
    Filed: January 6, 2006
    Publication date: June 8, 2006
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Akihiro Odagawa, Yasunari Sugita, Tsutomu Kanno, Akihiro Sakai, Hideaki Adachi
  • Patent number: 7042686
    Abstract: The present invention provides a magnetoresistive element that includes a pair of magnetic layers and an intermediate layer between the magnetic layers. The intermediate layer contains at least three elements selected from Groups 2 to 17, and the elements include at least one selected from the group consisting of F, O, N, C and B. According to the invention, a magnetoresistive element with high magnetoresistance change ratio and low resistance can be provided. The invention also provides a method for producing a magnetoresistive element. The method includes forming a precursor and forming at least one part of the intermediate layer from the precursor. The precursor is reacted with at least one reactive species selected from the group consisting of oxygen atoms, nitrogen atoms and carbon atoms in a reactive atmosphere containing the reactive species.
    Type: Grant
    Filed: June 18, 2004
    Date of Patent: May 9, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Akihiro Odagawa, Nozomu Matukawa, Kenji Iijima, Hiroshi Sakakima
  • Patent number: 7018725
    Abstract: A magneto-resistive effect element includes a first ferromagnetic film; a second ferromagnetic film; and a first nonmagnetic film interposed between the first ferromagnetic film and the second ferromagnetic film. The first ferromagnetic film has a magnetization more easily rotatable than a magnetization of the second ferromagnetic film by an external magnetic field. The first ferromagnetic film has an effective magnetic thickness of about 2 nm or less.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: March 28, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Akihiro Odagawa, Hiroshi Sakakima, Masayoshi Hiramoto, Nozomu Matsukawa
  • Patent number: 7012790
    Abstract: The present invention provides a magnetic head having improved characteristics, using a magnetoresistive device in which current flows across the film plane such as a TMR device. In a first magnetic head of the present invention, when the area of a non-magnetic layer is defined as a device cross-section area, and the area of a yoke is defined as a yoke area, viewed along the direction perpendicular to the surface of the substrate over which the yoke and the magnetoresistive device are formed, then the device cross-section area is not less than 30% of the yoke area, so that a resistance increase of the device cross-section area is suppressed. In a second magnetic head of the present invention, a magnetoresistive device is formed on a substrate, and a yoke is provided above a non-magnetic layer constituting the device.
    Type: Grant
    Filed: July 22, 2004
    Date of Patent: March 14, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
  • Publication number: 20060050549
    Abstract: A electro-resistance element with good heat treatment stability under a hydrogen-containing atmosphere and a electro-resistance memory with good resistance change characteristics and productivity are provided. The electro-resistance element has two or more states in which electric resistance values are different, and is switchable from one of the states selected from the two or more states into another by application of a predetermined voltage or current. The electro-resistance element includes a pair of electrodes, and an oxide semiconductor layer sandwiched by the pair of electrodes and having a perovskite structure, and the conductivity type of the oxide semiconductor layer is n-type. The electro-resistance memory is provided with the electro-resistance element.
    Type: Application
    Filed: November 7, 2005
    Publication date: March 9, 2006
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Hideaki Adachi, Yasunari Sugita, Akihiro Odagawa
  • Patent number: 7005691
    Abstract: A magnetoresistance element, wherein a first electric conductor is so formed as to contact almost the center of the surface opposite to a non-magnetic layer of a first ferromagnetic layer so formed as to sandwich, along with a second ferromagnetic layer, the non-magnetic layer, and an insulator so formed as to cover at least the side surface of the first ferromagnetic layer and the non-magnetic layer is formed so as to cover the peripheral edge of the surface of the first ferromagnetic layer, whereby it is possible to prevent a leakage current from flowing from the first electric conductor to a second electric conductor along the side surfaces of the first ferromagnetic layer, the non-magnetic layer and the second ferromagnetic layer, and to make uniform a bias current running from the first electric conductor to the second electric conductor to thereby restrict variations in magnetoresistance characteristics such as MR value and junction resistance.
    Type: Grant
    Filed: June 4, 2002
    Date of Patent: February 28, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Akihiro Odagawa, Masayoshi Hiramoto, Nozomu Matsukawa, Masahiro Deguchi
  • Publication number: 20060021646
    Abstract: The present invention provides a thermoelectric conversion device having high thermoelectric conversion performance. In this device, electrodes are arranged so that electric current flows in an interlayer direction of a layered substance, unlike the arrangements derived from common knowledge in the art. In the thermoelectric conversion device according to the present invention, a thermoelectric-conversion film is obtained through epitaxial growth and formed by arranging an electrically conducting layer and an electrically insulating layer alternately; the electrically conducting layer has an octahedral crystal structure in which a transition metal atom M is positioned at its center and oxygen atoms are positioned at its vertexes; and the electrically insulating layer includes a metal element or a crystalline metal oxide.
    Type: Application
    Filed: August 2, 2005
    Publication date: February 2, 2006
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Satoshi Yotsuhashi, Tsutomu Kanno, Hideaki Adachi, Akihiro Odagawa, Yasunari Sugita
  • Patent number: 6977799
    Abstract: The present invention provides a magnetic head having improved characteristics, using a magnetoresistive device in which current flows across the film plane such as a TMR device. In a first magnetic head of the present invention, when the area of a non-magnetic layer is defined as a device cross-section area, and the area of a yoke is defined as a yoke area, viewed along the direction perpendicular to the surface of the substrate over which the yoke and the magnetoresistive device are formed, then the device cross-section area is not less than 30% of the yoke area, so that a resistance increase of the device cross-section area is suppressed. In a second magnetic head of the present invention, a magnetoresistive device is formed on a substrate, and a yoke is provided above a non-magnetic layer constituting the device.
    Type: Grant
    Filed: July 22, 2004
    Date of Patent: December 20, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
  • Patent number: 6954372
    Abstract: A magnetic memory device that includes a magnetoresistive element, a conductive wire for generating magnetic flux that changes a resistance value of the magnetoresistive element, and at least one ferromagnetic member through which the magnetic flux passes. The ferromagnetic member forms a magnetic gap at a position where the magnetic flux passes through the magnetoresistive element. A length of the magnetoresistive element that is measured in a direction parallel to the magnetic gap is less than or equal to twice the length of the magnetic gap. A length of a path traced by the magnetic flux in the ferromagnetic member is less than or equal to 1.0 ?m. The length of the path is also greater than or equal to five times the thickness of the ferromagnetic member and/or is greater than or equal to a length of the ferromagnetic member in the direction of the drawing of the conductive wire divided by five.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: October 11, 2005
    Assignee: Matsushita Electric Co., Ltd.
    Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita
  • Patent number: 6950333
    Abstract: A magnetic memory of the present invention includes two or more memory layers and two or more tunnel layers that are stacked in the thickness direction of the layers. The two or more memory layers are connected electrically in series. A group of first layers includes at least one layer selected from the two or more memory layers. A group of second layers includes at least one layer selected from the two or more memory layers. A resistance change caused by magnetization reversal in the group of first layers differs from a resistance change caused by magnetization reversal in the group of second layers.
    Type: Grant
    Filed: October 24, 2003
    Date of Patent: September 27, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita, Yoshio Kawashima
  • Patent number: 6943041
    Abstract: The present invention provides a method for producing a magnetoresistive element including a tunnel insulating layer, and a first magnetic layer and a second magnetic layer that are laminated so as to sandwich the tunnel insulating layer, wherein a resistance value varies depending on a relative angle between magnetization directions of the first magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: September 13, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasunari Sugita, Akihiro Odagawa, Nozomu Matsukawa, Yoshio Kawashima, Yasunori Morinaga
  • Publication number: 20050174700
    Abstract: The present invention provides a magnetic head having improved characteristics, using a magnetoresistive device in which current flows across the film plane such as a TMR device. In a first magnetic head of the present invention, when the area of a non-magnetic layer is defined as a device cross-section area, and the area of a yoke is defined as a yoke area, viewed along the direction perpendicular to the surface of the substrate over which the yoke and the magnetoresistive device are formed, then the device cross-section area is not less than 30% of the yoke area, so that a resistance increase of the device cross-section area is suppressed. In a second magnetic head of the present invention, a magnetoresistive device is formed on a substrate, and a yoke is provided above a non-magnetic layer constituting the device.
    Type: Application
    Filed: July 22, 2004
    Publication date: August 11, 2005
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
  • Publication number: 20050167699
    Abstract: The present invention lowers a drive voltage of a RRAM, which is a promising low power consumption, high-speed memory and suppresses variations in the width of an electric pulse for realizing a same resistance change. The present invention provides a variable resistance element including: a first electrode; a layer in which its resistance is variable by applying an electric pulse thereto, the layer being formed on the first electrode; and a second electrode formed on the layer; wherein the layer has a perovskite structure; and the layer has at least one selected from depressions and protrusions in an interface with at least one electrode selected from the first electrode and the second electrode.
    Type: Application
    Filed: February 22, 2005
    Publication date: August 4, 2005
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Yasunari Sugita, Akihiro Odagawa, Hideaki Adachi, Satoshi Yotsuhashi, Tsutomu Kanno, Kiyoshi Ohnaka
  • Patent number: 6917492
    Abstract: A magnetoresistive element includes a pair of ferromagnetic layers and a non-magnetic layer arranged between the ferromagnetic layers. At least one of the ferromagnetic layers has a composition expressed by (MxLy)100-zRz at the interface with the non-magnetic layer. The non-magnetic layer includes at least one element selected from the group consisting of B, C, N, O, and P. Here, M is FeaCobNic, L is at least one element selected from the group consisting of Pt, Pd, Ir, and Rh, R is an element that has a lower free energy to form a compound with the element of the non-magnetic layer that is at least one selected from the group consisting of B, C, N, O, and P than does any other element included in the composition as M or L, and a, b, c, x, y, and z satisfy a+b+c=100, a?30, x+y=100, 0<y?35, and 0.1?z?20. This element can provide a high MR ratio. A method for manufacturing a magnetoresistive element includes a first heat treatment process at 200° C. to 330° C.
    Type: Grant
    Filed: June 27, 2003
    Date of Patent: July 12, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Yasunari Sugita, Mitsuo Satomi, Yoshio Kawashima
  • Publication number: 20050135020
    Abstract: The present invention provides a magnetoresistive (MR) element that is excellent in MR ratio and thermal stability and includes at least one magnetic layer including a ferromagnetic material M-X expressed by M100-aXa. Here, M is at least one selected from Fe, Co and Ni, X is expressed by X1bX2c,X3d (X1 is at least one selected from Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt and Au, X2 is at least one selected from Al, Sc, Ti, V, Cr, Mn, Ga, Ge, Y, Zr, Nb, Mo, Hf, Ta, W, Re, Zn and lanthanide series elements, and X3 is at least one selected from Si, B, C, N, O, P and S), and a, b, c and d satisfy 0.05?a?60, 0?b?60, 0?c?30, 0?d?20, and a=b+c+d.
    Type: Application
    Filed: February 16, 2005
    Publication date: June 23, 2005
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasunari Sugita, Masayoshi Hiramoto, Nozomu Matsukawa, Mitsuo Satomi, Yoshio Kawashima, Akihiro Odagawa
  • Publication number: 20050122828
    Abstract: A magnetic switching device of the present invention includes: at least one transition member; at least one electrode; and at least one free magnetic member. The transition member contains a perovskite compound that contains at least a rare earth element and an alkaline-earth metal, the electrode and the free magnetic member are arranged in parallel and in a noncontact manner on the transition member, at least one of the free magnetic members is coupled magnetically with the transition member, and the transition member undergoes at least ferromagnetism-antiferromagnetism transition by injecting or inducing electrons or holes, whereby a magnetization direction of at least one of the free magnetic members changes. This configuration is applicable to a magnetic memory that records/reads out magnetization information of the free magnetic layer and various magnetic devices that utilize a resistance change of the magnetoresistive effect portion.
    Type: Application
    Filed: September 28, 2004
    Publication date: June 9, 2005
    Applicants: Matsushita Electric Industrial Co., Ltd., National Institute of Advanced Industrial Science and Technology
    Inventors: Akihiro Odagawa, Hiroshi Sato, Toshikazu Yamada, Yuji Ishii, Isao Inoue, Hiroshi Akoh, Masashi Kawasaki, Hidenori Takagi
  • Patent number: 6887717
    Abstract: A magnetoresistive device including a high-resistivity layer (13), a first magnetic layer (12) and a second magnetic layer (14), the first magnetic layer (12) and the second magnetic layer (14) being arranged so as to sandwich the high-resistivity layer (13), wherein the high-resistivity layer (13) is a barrier for passing tunneling electrons between the first magnetic layer (12) and the second magnetic layer (14), and contains at least one element LONC selected from oxygen, nitrogen and carbon; at least one layer A selected from the first magnetic layer (12) and the second magnetic layer (14) contains at least one metal element M selected from Fe, Ni and Co, and an element RCP different from the metal element M; and the element RCP combines with the element LONC more easily in terms of energy than the metal element M. Accordingly, a novel magnetoresistive device having a low junction resistance and a high MR can be obtained.
    Type: Grant
    Filed: August 19, 2002
    Date of Patent: May 3, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Hiroshi Sakakima, Hideaki Adachi, Akihiro Odagawa