Patents by Inventor Eiichi Hirota
Eiichi Hirota 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).
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Patent number: 6757192Abstract: A magnetic recording element is composed of a first magnetic film to generate spin vortex by an external magnetic field and a second magnetic film having a magnetization perpendicular to the surfaces thereof, and also an insulating layer to control (repress) a current through the magnetic recording element which is formed between the first magnetic film and the second magnetic film. A given external magnetic field is applied to the magnetic recording element, to generate a spin vortex in the first magnetic film and then, generate a vertical magnetization at the center of the spin vortex. Then, a given data is written on the vertical magnetization.Type: GrantFiled: May 17, 2002Date of Patent: June 29, 2004Assignee: Hokkaido UniversityInventors: Koichi Mukasa, Makoto Sawamura, Kazuhisa Sueoka, Eiichi Hirota, Ryosho Nakane, Motonori Nakamura
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Patent number: 6750450Abstract: A scanning magnetism detector includes a probe made of a solid material formed of a single crystal having spin polarization and electrical conductivity properties. When the probe is brought into proximity with a magnetic substance, a surface condition of the magnetic substance can be detected by measuring tunnel current flow between the probe and the surface of the magnetic substance.Type: GrantFiled: March 5, 2002Date of Patent: June 15, 2004Assignee: Hokkaido UniversityInventors: Koichi Mukasa, Makoto Sawamura, Kazuhisa Sueoka, Eiichi Hirota
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Patent number: 6562486Abstract: An exchange coupling film of the present invention includes a ferromagnetic layer and a pinning layer which is provided in contact with the ferromagnetic layer for pinning a magnetization direction of the ferromagnetic layer, the pinning layer including an (AB)2Ox layer, wherein: O denotes an oxygen atom; 2.8<x<3.2; and a value t as defined by: t=(Ra+Ro)/(2·(Rb+Ro)) (where Ra, Rb and Ro denote the ion radii of the atoms A, B and O, respectively) satisfies 0.8<t<0.97.Type: GrantFiled: April 13, 2001Date of Patent: May 13, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Sakakima, Eiichi Hirota, Yasuhiro Kawawake, Mitsuo Satomi, Yasunari Sugita
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Publication number: 20020196658Abstract: A magnetic recording element is composed of a first magnetic film to generate spin vortex by an external magnetic field and a second magnetic film having a magnetization perpendicular to the surfaces thereof, and also an insulating layer to control (repress) a current through the magnetic recording element which is formed between the first magnetic film and the second magnetic film. A given external magnetic field is applied to the magnetic recording element, to generate a spin vortex in the first magnetic film and then, generate a vertical magnetization at the center of the spin vortex. Then, a given data is written on the vertical magnetization.Type: ApplicationFiled: May 17, 2002Publication date: December 26, 2002Applicant: HOKKAIDO UNIVERSITYInventors: Koichi Mukasa, Makoto Sawamura, Kazuhisa Sueoka, Eiichi Hirota, Ryosho Nakane, Motonori Nakamura
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Publication number: 20020149362Abstract: A scanning magnetism detector includes a probe made of a solid material formed of a single crystal having spin polarization and electrical conductivity properties. When the probe is brought into proximity with a magnetic substance, a surface condition of the magnetic substance can be detected by measuring tunnel current flow between the probe and the surface of the magnetic substance.Type: ApplicationFiled: March 5, 2002Publication date: October 17, 2002Inventors: Koichi Mukasa, Makoto Sawamura, Kazuhisa Sueoka, Eiichi Hirota
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Publication number: 20020006529Abstract: An exchange coupling film of the present invention includes a ferromagnetic layer and a pinning layer which is provided in contact with the ferromagnetic layer for pinning a magnetization direction of the ferromagnetic layer, the pinning layer including an (AB)2Ox layer, wherein: O denotes an oxygen atom; 2.8<x<3.Type: ApplicationFiled: April 13, 2001Publication date: January 17, 2002Inventors: Hiroshi Sakakima, Eiichi Hirota, Yasuhiro Kawawake, Mitsuo Satomi, Yasunari Sugita
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Patent number: 6258470Abstract: An exchange coupling film of the present invention includes a ferromagnetic layer and a pinning layer which is provided in contact with the ferromagnetic layer for pinning a magnetization direction of the ferromagnetic layer, the pinning layer including an (AB)2Ox layer, wherein: O denotes an oxygen atom; 2.8<x<3.2; and a value t as defined by: t=(Ra+Ro)/({square root over (2)}·(Rb+Ro)) (where Ra, Rb and Ro denote the ion radii of the atoms A, B and O, respectively) satisfies 0.8<t<0.97.Type: GrantFiled: January 12, 1999Date of Patent: July 10, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Sakakima, Eiichi Hirota, Yasuhiro Kawawake, Mitsuo Satomi, Yasunari Sugita
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Patent number: 5358576Abstract: In amorphous materials including at least one iron-transition metal of Fe, Co, and Ni, and at least one metalloid of B, C, Si, and P, excellent magnetic characteristics can be provided subject to the condition that 0.5 to 10 atomic % of the above-described iron-transition metals are substituted by Mn. In addition, when the amorphous material partially substituted with Mn as described above is further comprised of at least one element selected from Groups IIIa, IVa, Va, and VIa in the periodic table, the crystallization temperature is considerably raised.Type: GrantFiled: June 6, 1980Date of Patent: October 25, 1994Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Harufumi Senno, Hiroshi Sakakima, Masatsugu Yamaguchi, Eiichi Hirota
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Patent number: 5144060Abstract: An emulsifying agent for emulsion polymerization comprising at least one compound selected from the group consisting of (i) betaine esters of polyoxyalkylene alkyl ethers, (ii) betaine esters of polyoxyalkylene alkylphenyl ethers, (iii) betaine esters of polyoxyalkylene dialkylphenyl ethers, (iv) betaine esters of polyoxyalkylene phenyl ethers having two or more benzene nuclei, and (v) betaine esters of polyoxyalkylene polyol ethers. This emulsifying agent is suitable for use in the emulsion polymerization of polymer emulsions capable of forming a film having an excellent water resistance, transparency, and smoothness.Type: GrantFiled: August 15, 1990Date of Patent: September 1, 1992Assignee: Lion CorporationInventors: Hiroshi Morita, Eiichi Hirota, Yasuo Ishizaki
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Patent number: 4943612Abstract: An ultra-fine particulated polymer latex having an average particle size of 100 nm or less, a crosslinked structure and a glass transition temperature lower than a value calculated by a weight fraction method.Type: GrantFiled: December 3, 1987Date of Patent: July 24, 1990Assignee: Lion CorporationInventors: Hiroshi Morita, Eiichi Hirota, Yasuo Ishizaki
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Patent number: 4535376Abstract: A magnetic head includes at least a core for constituting a magnetic circuit and a magnetic gap formed in the core. The core comprises an amorphous magnetic metallic film formed on a non-magnetic high-resistance substrate so that one of the end faces of the non-magnetic high-resistance substrate and the amorphous magnetic metallic film may be brought into contact with a magnetic recording medium.Type: GrantFiled: March 15, 1982Date of Patent: August 13, 1985Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Noboru Nomura, Eiichi Hirota, Kiyotaka Wasa
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Patent number: 4488195Abstract: A magnetic head and a method of producing same, wherein the magnetic head includes a head core formed of metallic magnetic material and has a head gap formed in a portion of the head core adapted to be positioned against a recording medium, and windings mounted on the head core. The material forming the head core is amorphous and has the following composition:(Co.sub.1-x M'.sub.x).sub.a Zr.sub.b Si.sub.c B.sub.d, where M' is at least one element selected from the group consisting of Cr, Mn, Fe Ni, Nb, Mo, W and Ti, 0.03.ltoreq.x.ltoreq.0.15, 3.ltoreq.b.ltoreq.25, 0.ltoreq.c.ltoreq.20, 0.ltoreq.d.ltoreq.5, and a+b+c+d=100.Type: GrantFiled: March 15, 1982Date of Patent: December 11, 1984Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yukihiro Yanagiuchi, Eiichi Hirota, Hiroshi Sakakima, Harufumi Senno
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Patent number: 4437912Abstract: Amorphous alloy consisting mainly of 60-94 atomic % of at least one transition metal, and over 2 atomic % but below 20 atomic % of niobium. The amorphous alloys according to the invention are high in wear resistance and corrosion resistance and have a high saturated magnetic flux density and soft magnetic properties. The amorphous alloys have particular utility as core materials for magnetic heads.Type: GrantFiled: November 16, 1981Date of Patent: March 20, 1984Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Sakakima, Mitsuo Satomi, Harufumi Senno, Eiichi Hirota
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Patent number: 4312683Abstract: Amorphous alloy films are heat-treated in the presence of a magnetic field directed in a particular direction so as to suppress induced magnetic anisotropy in the film. The directed magnetic field includes a vertical magnetic field whose direction is perpendicular to the plane of the film, and a rotating magnetic field whose direction is being rapidly changed within a parallel plane with respect to the plane of the amorphous alloy film.Type: GrantFiled: September 5, 1980Date of Patent: January 26, 1982Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Sakakima, Harufumi Senno, Yukihiro Yanagiuchi, Eiichi Hirota
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Patent number: 4288307Abstract: In a method of making a magnetic gap by depositing a glass layer on a surface of magnetic head core materials by cathodic sputtering of a glass target and cementing a pair of the resulting glass-coated magnetic head core materials, the improvements constituted by monitoring the thickness of the sputtered glass layer by an interference of a light beam guided onto a surface of the magnetic head core materials during the deposition and using a sputtering apparatus having a sample holder beside the target for securing the magnetic core materials and a mask plate for achieving uniform thickness of the sputtered glass layer.The method makes possible production of magnetic heads having excellent electromagnetic conversion characteristics with high accuracy.Type: GrantFiled: February 19, 1980Date of Patent: September 8, 1981Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kiyotaka Wasa, Takao Tohda, Kazuo Yokoyama, Eiichi Hirota, Shigeru Hayakawa
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Patent number: 4288260Abstract: A method of heat treatments of amorphous alloy ribbons comprises the sequential steps of; grinding amorphous alloy ribbon continuously fed at a predetermined speed (V) selectively varied in the range of 1 cm/sec.ltoreq.V.ltoreq.50 cm/sec, to uniformly finish the ribbon, and successively, heat-treating the ribbon with its surface contacting a stationary or rotating heating body having a surface temperature (T) defined in the range of (T.sub.cry -200.degree. C.).ltoreq.V.ltoreq.(T.sub.cry +50.degree. C.), where T.sub.cry is a crystallization point temperature of the alloy, to uniformly enhance the magnetic properties of the ribbon, and to remove the specific curlings inherently caused by so-called splat cooling manufacturing method, without causing any developments of brittleness of the ribbon mentioned above.Type: GrantFiled: March 26, 1980Date of Patent: September 8, 1981Assignee: Matsushita Electric Industrial Co. Ltd.Inventors: Harufumi Senno, Hiroshi Sakakima, Yukihiro Yanagiuchi, Tsuneo Inoue, Masatsugu Yamaguchi, Eiichi Hirota
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Patent number: 4064224Abstract: A method of making fibrous alkali titanates comprising the steps of preparing a mixture including a titanium compound and an alkali metal compound in a molar ratio of 1.0 to 8.0 in terms of TiO.sub.2 :M.sub.2 O (M: Na, K, Rb, Cs), heating said mixture at a temperature of 1200.degree. to 1600.degree. C to the molten (liquid) phase, cooling the thus heated mixture to room temperature , and washing the thus treated product. This method is advantageous because fibrous alkali titanates of large ratio of length to diameter can be easily produced in high yield.Type: GrantFiled: January 28, 1976Date of Patent: December 20, 1977Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takashi Kawamata, Tsuneo Inoue, Eiichi Hirota
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Patent number: 3956151Abstract: A method for producing, under a low pressure such as an ambient atmospheric pressure, a ferromagnetic chromium oxide having a sufficiently high saturation magnetization and, if necessary, sufficiently high coercive force as well. The main feature of this method is to use H.sub.2 O.sub.2 in conjunction with CrO.sub.3 and, if necessary, Te, Sb or an alkali element as well and to heat them.Type: GrantFiled: July 22, 1974Date of Patent: May 11, 1976Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tadashi Kawamata, Eiichi Hirota, Yukio Terada
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Patent number: 3954641Abstract: The present invention provides a ferromagnetic chromium oxide powder having an additive of sulfur incorporated therewith, which powder has a lower curie temperature than that of pure chromium dioxide powder and a high saturation magnetization. Said powder has a composition in weight percent, consisting essentially of 61.90 to 57.22 percent of chromium and 0.0038 to 15.10 percent of sulfur. Moreover, the ferromagnetic chromium oxide powder having a combination of sulfur and further additives selected from tellurium, tin and antimony has a lower Curie temperature than that of pure chromium dioxide together with a high intrinsic coercive force and a high saturation magnetization. The particles of these powders are in a uniform acicular shape and are useful in magnetic recording media, especially for slave tapes in thermo-magnetic duplication.Type: GrantFiled: August 31, 1973Date of Patent: May 4, 1976Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tadashi Kawamata, Toshihiro Mihara, Yukio Terada, Eiichi Hirota
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Patent number: 3931642Abstract: This invention provides a magnetic head constituted by a magnetic core having a winding wound thereon, the magnetic core being a ferrite body composed of crystallites which have (111)-crystallographic planes thereof oriented substantially parallel with each other. The ferrite body is a dense polycrystalline and has much improved wear characteristics. The method of manufacturing the polycrystalline ferrite body includes the steps of mixing starting materials which include an .alpha.-Fe.sub.2 O.sub.3 powder with particles having a thin disc shape and other compounds in the weight ratio of given ferrite composition, cold-pressing the mixture into a cold-pressed body by a uniaxial pressure and sintering the cold-pressed body into a solid body so that the crystallites of the sintered body have the (111) 111)-planes substantially oriented.Type: GrantFiled: June 15, 1973Date of Patent: January 6, 1976Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Koichi Kugimiya, Eiichi Hirota