Patents by Inventor Toyoji Ataka
Toyoji Ataka 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: 9659592Abstract: A perpendicular magnetic recording medium exhibits reduced noise and improved performance in such measures as SN ratio, and can realize high magnetic recording densities. In the perpendicular magnetic recording medium, at least a first nonmagnetic intermediate layer, second nonmagnetic intermediate layer, and magnetic recording layer are stacked in order on a nonmagnetic substrate. The first nonmagnetic intermediate layer is formed from a CoCrRuW alloy, and the second nonmagnetic intermediate layer is formed from an Ru-base alloy.Type: GrantFiled: May 1, 2012Date of Patent: May 23, 2017Assignee: FUJI ELECTRIC CO., LTD.Inventors: Toyoji Ataka, Shunji Takenoiri, Sadayuki Watanabe, Hirohisa Oyama, Yasuaki Hozumi, Satoshi Takahashi
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Publication number: 20130209836Abstract: A perpendicular magnetic recording medium exhibits reduced noise and improved performance in such measures as SN ratio, and can realize high magnetic recording densities. In the perpendicular magnetic recording medium, at least a first nonmagnetic intermediate layer, second nonmagnetic intermediate layer, and magnetic recording layer are stacked in order on a nonmagnetic substrate. The first nonmagnetic intermediate layer is formed from a CoCrRuW alloy, and the second nonmagnetic intermediate layer is formed from an Ru-base alloy.Type: ApplicationFiled: May 1, 2012Publication date: August 15, 2013Applicant: FUJI ELECTRIC CO., LTD.Inventors: Toyoji Ataka, Shunji Takenoiri, Sadayuki Watanabe, Hirohisa Oyama, Yasuaki Hozumi, Satoshi Takahashi
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Publication number: 20080044688Abstract: A high-recording-density magnetic recording medium and a method of its manufacture can achieve a high OR with only a small reduction in Hcr. The magnetic recording medium has a nonmagnetic substrate and a first seed layer, a second seed layer, a first underlayer, a second underlayer, and a magnetic recording layer formed on the substrate in this order. The first seed layer can be a single layer or a plurality of layers made of at least one material selected from the group consisting of Ni—Ti alloys, Cr—Al alloys, Cr—Ta alloys, and Cr—Ti alloys. The second seed layer can be a single layer or a plurality of layers made of at least one material selected from the group consisting of Ni—W alloys, Ni—Ru—W alloys, and Co—W alloys. The first underlayer can be a single layer or a plurality of layers made of a Cr—Ru alloy. The second underlayer can be a single layer or a plurality of layers made of a Cr alloy comprising Cr and at least one element selected from the group consisting of Mo, B, Ti, and W.Type: ApplicationFiled: March 7, 2007Publication date: February 21, 2008Applicant: FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD.Inventors: Tuqiang Li, Manabu Shimosato, Toyoji Ataka, Hiromi Ono, Kenichiro Soma, Hiroyuki Uwazumi, Souta Matsuo
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Publication number: 20060115686Abstract: A high-density magnetic recording medium uses a nonmetallic substrate, while still providing high in-plane magnetic anisotropy and remanent coercivity. Such a medium can be formed by depositing a seed layer on a textured surface of the nonmetallic substrate in a gas mixture containing oxygen or nitrogen and an inert gas, while controlling the oxygen concentration or nitrogen concentration, and subsequently exposing the surface of the seed layer to oxygen or nitrogen.Type: ApplicationFiled: January 17, 2006Publication date: June 1, 2006Applicant: Fuji Electric Co., Ltd.Inventors: Toyoji Ataka, Satoru Nakamura, Katsuya Masuda, Ryoichi Kadota, Yuji Ando
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Patent number: 7014882Abstract: A high-density magnetic recording medium uses a nonmetallic substrate, while still providing high in-plane magnetic anisotropy and remanent coercivity. Such a medium can be formed by depositing a seed layer on a textured surface of the nonmetallic substrate in a gas mixture containing oxygen or nitrogen and an inert gas, while controlling the oxygen concentration or nitrogen concentration, and subsequently exposing the surface of the seed layer to oxygen or nitrogen.Type: GrantFiled: March 13, 2003Date of Patent: March 21, 2006Assignee: Fuji Electric Co., Ltd.Inventors: Toyoji Ataka, Satoru Nakamura, Katsuya Masuda, Ryoichi Kadota, Yuji Ando
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Patent number: 6849164Abstract: A magnetic recording medium and method of manufacturing the same including directly texturing a surface of a non-magnetic substrate made of a glass material to form circular concentric grooves thereon, forming a seed layer on the non-magnetic substrate, forming an under layer on the seed layer, forming a magnetic layer on the under layer, and forming a protective layer on the magnetic layer. A ratio of an in-plane remanent magnetization in a circumferential direction of the magnetic recording medium to an in-plane remanent magnetization in a radial direction of the magnetic recording medium is equal to or greater than 1.05.Type: GrantFiled: May 10, 2002Date of Patent: February 1, 2005Assignee: Fuji Electric Co., Ltd.Inventors: Toyoji Ataka, Yuji Ando, Satoru Nakamura, Katsuya Masuda, Manabu Shimosato
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Patent number: 6764721Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.Type: GrantFiled: October 20, 2003Date of Patent: July 20, 2004Assignee: Fuji Electric Co., Ltd.Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
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Publication number: 20040072037Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.Type: ApplicationFiled: October 20, 2003Publication date: April 15, 2004Applicant: FUJI ELECTRIC CO., LTD.Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
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Publication number: 20040009372Abstract: A high-density magnetic recording medium uses a nonmetallic substrate, while still providing high in-plane magnetic anisotropy and remanent coercivity. Such a medium can be formed by depositing a seed layer on a textured surface of the nonmetallic substrate in a gas mixture containing oxygen or nitrogen and an inert gas, while controlling the oxygen concentration or nitrogen concentration, and subsequently exposing the surface of the seed layer to oxygen or nitrogen.Type: ApplicationFiled: March 13, 2003Publication date: January 15, 2004Inventors: Toyoji Ataka, Satoru Nakamura, Katsuya Masuda, Ryoichi Kadota, Yuji Ando
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Patent number: 6667117Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.Type: GrantFiled: March 8, 2001Date of Patent: December 23, 2003Assignee: Fuji Electric Co., Ltd.Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
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Publication number: 20030012983Abstract: A magnetic recording medium and method of manufacturing the same including directly texturing a surface of a non-magnetic substrate made of a glass material to form circular concentric grooves thereon, forming a seed layer on the non-magnetic substrate, forming an under layer on the seed layer, forming a magnetic layer on the under layer, and forming a protective layer on the magnetic layer. A ratio of an in-plane remanent magnetization in a circumferential direction of the magnetic recording medium to an in-plane remanent magnetization in a radial direction of the magnetic recording medium is equal to or greater than 1.05.Type: ApplicationFiled: May 10, 2002Publication date: January 16, 2003Inventors: Toyoji Ataka, Yuji Ando, Satoru Nakamura, Katsuya Masuda, Manabu Shimosato
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Publication number: 20010038932Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.Type: ApplicationFiled: March 8, 2001Publication date: November 8, 2001Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
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Patent number: 6037069Abstract: A magnetic recording medium has a non-magnetic metal base layer formed on a non-magnetic base and supporting a magnetic layer thereon. The non-magnetic metal base layer includes two or more base layers including at least one first base layer each having an anisotropic magnetic characteristic in which a coercive force in a circumferential direction of the magnetic recording medium is higher than a coercive force in a radial direction of the medium, and at least one second base layer each having an anisotropic magnetic characteristic in which the coercive force in the circumferential direction is lower than the coercive force in the radial direction.Type: GrantFiled: May 30, 1996Date of Patent: March 14, 2000Assignee: Fuji Electric Co., Ltd.Inventors: Toyoji Ataka, Keiji Okubo, Masashi Kanamori
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Patent number: 5939202Abstract: A magnetic recording medium is provided which includes a non-magnetic base, and a non-magnetic metal base layer, a magnetic layer, and a protective layer, which are laminated in the order of description on the non-magnetic base, wherein the non-magnetic metal base layer is formed from an alloy film in which at least one element selected from the group consisting of W, Ta, Hf, Mo, Cr, Zr and Nb is added to NiAl.Type: GrantFiled: October 7, 1997Date of Patent: August 17, 1999Assignee: Fuji Electric Co., Ltd.Inventors: Toyoji Ataka, Keiji Ohkubo, Noboru Kurata, Naoki Takizawa, Kazuo Enomoto
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Patent number: 5891514Abstract: In a method for manufacturing a magnetic recording medium, a non-metallic metal base layer, a ferromagnetic alloy thin-film magnetic layer and a protective layer are successively laminated on a non-magnetic substrate. The ferromagnetic alloy thin-film magnetic layer consists of a first magnetic layer and a second magnetic layer. In the method of the present invention, the first magnetic layer is formed in an atmosphere containing an Ar gas, and the second magnetic layer is formed in an atmosphere containing a mixture of Ar and N.sub.2 gases.Type: GrantFiled: November 17, 1997Date of Patent: April 6, 1999Assignee: Fuji Electric Co., Ltd.Inventors: Toyoji Ataka, Keiji Ohkubo
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Patent number: 5576098Abstract: A thin film magnetic head includes an upper magnetic core film and a lower magnetic core film laminated one on another through a magnetic gap layer. The upper and lower magnetic core films are multilayer thin films, respectively, each of which is composed of a plurality of magnetic thin film layers and a plurality of non-magnetic thin film layers, alternately laminated one on another. The magnetic core films and have single domain structures, respectively, and the use of such magnetic core films realizes a thin film magnetic head having high permeability at high frequencies and improved high frequency characteristics and attains high recording density.Type: GrantFiled: July 6, 1993Date of Patent: November 19, 1996Assignee: Fuji Electric Co., Ltd.Inventors: Yuko Arimoto, Takabumi Fumoto, Keiji Okubo, Osamu Saito, Toyoji Ataka, Hisashi Yamasaki
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Patent number: 5503686Abstract: A magnetic recording head that includes a combined IN element and an MR element is heat treated under two types of magnetic fields. A rotating magnetic field, having a first magnetic field intensity, is applied for a time while the magnetic recording head is at an elevated temperature. Then, part-way during cooling of the magnetic head, the rotating magnetic field is replaced by a direct (non-rotating) magnetic field having a second magnetic field intensity. The second magnetic field intensity is lower than the first magnetic field intensity, whereby the properties of both the IN element and the MR element are maintained at high values.Type: GrantFiled: March 13, 1995Date of Patent: April 2, 1996Assignee: Fuji Electric Co., Ltd.Inventors: Yuko Okamura, Keiji Ohkubo, Osamu Saito, Toyoji Ataka