Patents by Inventor Hiroyuki Uwazumi
Hiroyuki Uwazumi 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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Publication number: 20070059561Abstract: The quantity of oxide contained in a magnetic layer is controlled to control the crystal grains and the segregation structure for ensuring low noise characteristic in a granular magnetic layer of a perpendicular magnetic recording medium. The granular magnetic layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary region mainly of an oxide surrounding the ferromagnetic crystal grains. The perpendicular magnetic recording medium has a nonmagnetic underlayer composed of a metal or alloy having hexagonal closest-packed crystal structure. The ferromagnetic crystal grain is composed of an alloy containing at least cobalt and platinum. The volume proportion of the nonmagnetic grain boundary region mainly of the oxide falls within a range of 15% to 40% of the volume of the total magnetic layer.Type: ApplicationFiled: August 31, 2006Publication date: March 15, 2007Applicant: FUJI ELECTRIC HOLDINGS CO., LTD.Inventors: Hiroyuki UWAZUMI, Yasushi SAKAI, Tadaaki OIKAWA, Miyabi NAKAMURA
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Patent number: 7183011Abstract: A magnetic recording medium for perpendicular magnetic recording system includes a nonmagnetic substrate and layers sequentially laminated on the substrate. The layers include a seed layer comprised of a metal or an alloy with a face centered cubic crystal structure, a nonmagnetic underlayer of a metal or an alloy with a hexagonal closest packed crystal structure, a magnetic layer having a granular structure including ferromagnetic crystalline grains with a hexagonal closest packed structure and nonmagnetic grain boundary region of mainly oxide surrounding the crystalline grains, a protective layer, and a liquid lubricant layer.Type: GrantFiled: January 17, 2003Date of Patent: February 27, 2007Assignee: Fuji Electric Co., Ltd.Inventors: Miyabi Nakamura, Takahiro Shimizu, Hiroyuki Uwazumi, Naoki Takizawa, Tadaaki Oikawa
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Patent number: 7183013Abstract: A nonmagnetic foundation layer is made to have a body-centered cubic crystal structure with a preferred crystal orientation plane being the bcc (110) plane. A nonmagnetic intermediate layer, provided between the foundation layer and a granular magnetic layer, has a hexagonal close-packed structure with the hcp (100) plane or the hcp (200) plane being the preferred orientation plane. Furthermore, the crystal lattice misfit amount between the nonmagnetic intermediate layer 3 and the granular magnetic layer is made to be not more than 10% for each of an a-axis and a c-axis. As a result, epitaxial growth of ferromagnetic crystals in the granular magnetic layer, which has an hcp structure, is promoted, and hence the crystallinity of the magnetic layer is increased, and thus it becomes possible to simultaneously realize an increase in coercivity and a reduction in noise. Depositing the layers on an unheated substrate yields reduces manufacturing costs.Type: GrantFiled: January 26, 2004Date of Patent: February 27, 2007Assignee: Fuji Electric Device Technology Co., Ltd.Inventors: Tadaaki Oikawa, Takahiro Shimizu, Hiroyuki Uwazumi, Naoki Takizawa
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Patent number: 7160571Abstract: A method of manufacturing a magnetic recording medium facilitates preventing a film inflation from occurring in an environmental condition range between ?40° C. and 80° C. and an 80% relative humidity. The magnetic recording medium includes a plastic substrate and an undercoating layer on the plastic substrate. The undercoating layer is provided with a columnar structure, which prevents water (moisture) between the plastic substrate and the undercoating layer from aggregating and, therefore, the film inflation from occurring.Type: GrantFiled: August 11, 2004Date of Patent: January 9, 2007Assignee: Fuji Electric Co., Ltd.Inventors: Akira Iso, Hiroyuki Uwazumi, Takahiro Shimizu, Naoki Takizawa, Miyabi Nakamura
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Patent number: 7147942Abstract: The quantity of oxide contained in a magnetic layer is controlled to control the crystal grains and the segregation structure for ensuring low noise characteristic in a granular magnetic layer of a perpendicular magnetic recording medium. The granular magnetic layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary region mainly of an oxide surrounding the ferromagnetic crystal grains. The perpendicular magnetic recording medium has a nonmagnetic underlayer composed of a metal or alloy having hexagonal closest-packed crystal structure. The ferromagnetic crystal grain is composed of an alloy containing at least cobalt and platinum. The volume proportion of the nonmagnetic grain boundary region mainly of the oxide falls within a range of 15% to 40% of the volume of the total magnetic layer.Type: GrantFiled: December 9, 2002Date of Patent: December 12, 2006Assignee: Fuji Electric Co., Ltd.Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Tadaaki Oikawa, Miyabi Nakamura
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Publication number: 20060147760Abstract: A perpendicular magnetic recording medium is provided that achieves excellent magnetic performance by suppressing spike noises due to a soft magnetic backing layer, as well as good productivity. The perpendicular magnetic recording medium comprises at least a soft magnetic backing layer, an antiferromagnetic layer, an nonmagnetic underlayer, and a magnetic recording layer sequentially laminated on a nonmagnetic substrate, wherein the magnetic recording layer has a granular structure, the nonmagnetic underlayer is composed of ruthenium or a ruthenium alloy having an hcp structure having a thickness of at least 5 nm, the antiferromagnetic layer is composed of an alloy having an fcc structure and containing at least manganese, and the antiferromagnetic layer is laminated directly on the soft magnetic backing layer. Preferably, the antiferromagnetic layer is composed of an IrMn alloy, and the soft magnetic backing layer has an fcc structure and contains at least nickel and iron.Type: ApplicationFiled: December 2, 2005Publication date: July 6, 2006Applicant: Fuji Electric Device Technology Co., Ltd.Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Shunji Takenoiri, Sadayuki Watanabe
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Patent number: 7067206Abstract: A perpendicular magnetic recording medium has a granular magnetic layer and a nonmagnetic underlayer of a metal or an alloy having a hexagonal close packed (hcp) crystal structure. A seed layer of a metal or an alloy of a face-centered cubic (fcc) crystal structure is provided under the nonmagnetic underlayer. Such a perpendicular magnetic recording medium exhibits excellent magnetic characteristics even when the thickness of the underlayer or the total thickness of the underlayer and the seed layer is very thin. Excellent magnetic characteristics can be obtained even when of the substrate is not preheated. Accordingly, a nonmagnetic substrate, such as a plastic resin can be employed to reduce the manufacturing cost.Type: GrantFiled: August 23, 2002Date of Patent: June 27, 2006Assignee: Fuji Electric Co., Ltd.Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Tadaaki Oikawa, Miyabi Nakamura
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Patent number: 6994924Abstract: A magnetic recording medium and a manufacturing method therefore includes a protective film, a nonmagnetic substrate, a nonmagnetic base layer, a nonmagnetic intermediate layer, a magnetic layer, and a liquid lubricant layer. The nonmagnetic base layer has a body-centered cubic structure and a (200) plane including a crystal-orientation parallel with a surface of the protective film. The nonmagnetic intermediate layer has a hexagonal close-packed structure and a (110) plane including a crystal-orientation parallel with the surface of the protective film. The magnetic layer has a granular structure including hexagonal close-packed ferromagnetic crystal grains and oxide-based nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains. The nonmagnetic base layer, the nonmagnetic intermediate layer, the magnetic layer, the protective film, and the liquid lubricant layer are sequentially stacked on the nonmagnetic substrate.Type: GrantFiled: October 18, 2002Date of Patent: February 7, 2006Assignee: Fuji Electric Co., Ltd.Inventors: Tadaaki Oikawa, Takahiro Shimizu, Hiroyuki Uwazumi, Naoki Takizawa, Myabi Nakamura
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Publication number: 20060024431Abstract: An object of the present invention is to provide a plating method on a glass base plate. The method allows forming a plating film on a base plate composed of a glass material with excellent adhesivity and homogeneity by means of an electroless plating method even to a thickness of 1 ?m or more. Before forming a plating film by a step of electroless plating S6, a surface treatment process is conducted on a surface of the base plate composed of a glass material. The surface treatment process comprises at least a step of glass activation treatment S2 to increase quantity of silanol groups on the surface of the base plate at least by a factor of two using an aqueous solution of diluted acid, a step of silane coupling agent treatment S3, a step of palladium catalyst treatment S4, and a step of palladium bonding treatment S5.Type: ApplicationFiled: July 27, 2005Publication date: February 2, 2006Applicant: Fuji Electric DeviceInventors: Youichi Tei, Akira Iso, Kazuhito Higuchi, Hajime Kurihara, Hiroyuki Uwazumi
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Publication number: 20060014051Abstract: A perpendicular magnetic recording medium and a method of manufacturing the same include a nonmagnetic substrate, a nonmagnetic underlayer, and a magnetic layer disposed directly on the nonmagnetic underlayer. The magnetic layer is composed of ferromagnetic crystal grains having a hexagonal close-packed structure and nonmagnetic grain boundaries composed of oxide or nitride surrounding each of the ferromagnetic crystal grains. The surface energy of the nonmagnetic underlayer is made to be at least 70 mN/m. The nonmagnetic underlayer can be composed of a metal selected from rhenium, ruthenium, and osmium, or an alloy containing at least an element selected from rhenium, ruthenium, and osmium, and can have a thickness of 30 nm or less.Type: ApplicationFiled: June 16, 2005Publication date: January 19, 2006Applicant: Fuji Electric Device Technology Co., Ltd.Inventors: Akiro Iso, Hiroyuki Uwazumi
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Publication number: 20050238929Abstract: A disk substrate for a perpendicular magnetic recording medium is, disclosed. The substrate exhibits sufficient productivity, serves the function of a soft magnetic backing layer of the perpendicular magnetic recording medium, and scarcely generates noise. A perpendicular magnetic recording medium using such a substrate also is disclosed. The disk substrate comprises at least a soft magnetic underlayer formed on a nonmagnetic base plate by means of an electroless plating method. The thermal expansion coefficient of the soft magnetic underlayer is larger than a thermal expansion coefficient of the nonmagnetic disk-shaped base plate. A saturation magnetostriction constant ?s satisfies a relation ?s??1×10?5.Type: ApplicationFiled: April 12, 2005Publication date: October 27, 2005Applicant: Fuji Electric DeviceInventors: Hiroyuki Uwazumi, Youichi Tei, Kengo Kainuma, Kazuhito Higuchi, Akira Iso, Hajime Kurihara
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Publication number: 20050238926Abstract: A substrate for a perpendicular magnetic recording medium and a perpendicular magnetic recording medium using such a substrate are disclosed. The substrate exhibits sufficient productivity and functions as a soft magnetic backing layer of a perpendicular magnetic recording medium based on the substrate, ensuring surface hardness. The substrate comprises a nonmagnetic base plate composed of an aluminum alloy, an adhesion layer formed on the nonmagnetic base plate and composed of a material containing at least nickel, and a soft magnetic underlayer formed on the adhesion layer by means of an electroless plating method. The soft magnetic underlayer contains phosphorus in a range of 3 at % to 20 at %, and at least 25 at % of cobalt in proportion to the number of atoms of cobalt and nickel excluding the phosphorus (Co/(Co+Ni)). Thickness of the adhesion layer is at least 0.1 ?m. Thickness of the soft magnetic underlayer is at least 0.Type: ApplicationFiled: March 11, 2005Publication date: October 27, 2005Applicant: Fuji Electric Device Technology Co., LtdInventors: Hiroyuki Uwazumi, Norihiko Nakajima, Tatsumi Kawata, Kazuhito Higuchi
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Publication number: 20050196642Abstract: A magnetic recording medium, and method of manufacturing the same, is provided with excellent recording performance by employing a granular magnetic layer having a specified composition. A magnetic recording medium according to the present invention comprises a nonmagnetic underlayer, a granular magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on a nonmagnetic substrate. The granular magnetic layer consists of ferromagnetic crystal grains containing cobalt and nonmagnetic grain boundary region surrounding the ferromagnetic crystal grains. The ferromagnetic crystal grains contain platinum in the range of 15 at % to 17 at %.Type: ApplicationFiled: April 26, 2005Publication date: September 8, 2005Applicant: Fuji Electric Co., Ltd.Inventors: Miyabi Nakamura, Takahiro Shimizu, Hiroyuki Uwazumi, Naoki Takizawa, Tadaaki Oikawa
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Publication number: 20050186358Abstract: A perpendicular magnetic recording medium and method thereof, includes a nonmagnetic substrate; a soft magnetic under layer; an intermediate layer; a bilayer magnetic recording layer; a protective layer; and a liquid lubricant layer. According to a following order, the soft magnetic under layer, the intermediate layer, the bilayer magnetic recording layer, the protective layer, and the liquid lubricant layer are sequentially stacked on the nonmagnetic substrate. The bilayer magnetic recording layer includes a first magnetic layer including a CoCr alloy crystalline film, and a second magnetic layer including a rare earth-transition metal alloy noncrystalline film.Type: ApplicationFiled: April 27, 2005Publication date: August 25, 2005Applicant: FUJI ELECTRONIC CO., LTD.Inventors: Yasushi Sakai, Hiroyuki Uwazumi, Kazuo Enomoto, Sadayuki Watanabe
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Publication number: 20050181237Abstract: There is provided a perpendicular magnetic recording medium according to which both the thermal stability of the magnetization is good and writing with a magnetic head is easy, and moreover the SNR is improved. In the case of a perpendicular magnetic recording medium comprising a nonmagnetic substratel, and at least a nonmagnetic underlayer 2, a magnetic recording layer 3 and a protective layer 4 formed in this order on the nonmagnetic substrate 1, the magnetic recording layer 3 comprises a low Ku region 31 layer having a perpendicular magnetic anisotropy constant (Ku value) of not more than 1×105 erg/cm3, and a high Ku region 32 layer having a Ku value of at least 1×106 erg/cm3. Moreover, the magnetic recording layer 3 is made to have therein nonmagnetic grain boundaries that contain a nonmagnetic oxide and magnetically isolate crystal grains, which are made of a ferromagnetic metal, from one another.Type: ApplicationFiled: January 10, 2005Publication date: August 18, 2005Inventors: Osamu Kitakami, Yutaka Shimada, Satoshi Okamoto, Takehito Shimatsu, Hajime Aoi, Hiroaki Muraoka, Yoshihisa Nakamura, Hiroyuki Uwazumi, Tadaaki Oikawa
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Publication number: 20050153169Abstract: A perpendicular magnetic recording medium has a magnetic recording layer and laminated magnetic layers composed of different materials. In a first magnetic layer of the magnetic recording layer, ferromagnetic grains are surrounded by a nonmagnetic grain boundary region composed principally of oxide and/or nitride. In a second magnetic layer of the magnetic recording layer, ferromagnetic grains are surrounded by a nonmagnetic grain boundary region composed principally of chromium. The recording medium has an intermediate layer composed of a material having hcp or fcc structure. Advantageously, a heating process is conducted after forming the first magnetic layer and before forming the second magnetic layer. The medium achieves improvement in electromagnetic conversion characteristics and simultaneously improvement in corrosion resistance to provide a perpendicular magnetic recording medium with high recording density and simultaneously high reliability.Type: ApplicationFiled: June 14, 2004Publication date: July 14, 2005Inventors: Sadayuki Watanabe, Yasushi Sakai, Hiroyuki Uwazumi
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Patent number: 6913837Abstract: A perpendicular magnetic recording medium and method thereof, includes a nonmagnetic substrate; a soft magnetic under layer; an intermediate layer; a bilayer magnetic recording layer; a protective layer; and a liquid lubricant layer. According to a following order, the soft magnetic under layer, the intermediate layer, the bilayer magnetic recording layer, the protective layer, and the liquid lubricant layer are sequentially stacked on the nonmagnetic substrate. The bilayer magnetic recording layer includes a first magnetic layer including a CoCr alloy crystalline film, and a second magnetic layer including a rare earth-transition metal alloy noncrystalline film.Type: GrantFiled: July 8, 2002Date of Patent: July 5, 2005Assignee: Fuji Electric Co., Ltd.Inventors: Yasushi Sakai, Hiroyuki Uwazumi, Kazuo Enomoto, Sadayuki Watanabe
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Patent number: 6899964Abstract: A magnetic recording medium, and method of manufacturing the same, is provided with excellent recording performance by employing a granular magnetic layer having a specified composition. A magnetic recording medium according to the present invention comprises a nonmagnetic underlayer, a granular magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on a nonmagnetic substrate. The granular magnetic layer consists of ferromagnetic crystal grains containing cobalt and nonmagnetic grain boundary region surrounding the ferromagnetic crystal grains. The ferromagnetic crystal grains contain platinum in the range of 15 at % to 17 at %.Type: GrantFiled: December 11, 2002Date of Patent: May 31, 2005Assignee: Fuji Electric Co., Ltd.Inventors: Miyabi Nakamura, Takahiro Shimizu, Hiroyuki Uwazumi, Naoki Takizawa, Tadaaki Oikawa
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Patent number: 6884520Abstract: A perpendicular magnetic recording medium has a nonmagnetic substrate, a nonmagnetic underlayer, a magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on the substrate. The nonmagnetic layer is composed of a metal or alloy having a hcp crystal structure. The magnetic recording layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary phase mainly composed of an oxide surrounding the grains. A seed layer of a metal or alloy having a fcc crystal structure can be provided under the nonmagnetic underlayer, and a nonmagnetic alignment control layer can be provided under the seed layer. The recording medium can provide high output and low noise by improving the alignment of the magnetic recording layer, reducing the initial growth layer in the magnetic recording layer, and minimizing the grain size of the magnetic recording layer.Type: GrantFiled: December 9, 2002Date of Patent: April 26, 2005Assignee: Fuji Electric Co., Ld.Inventors: Tadaaki Oikawa, Hiroyuki Uwazumi, Shunji Takenoiri, Miyabi Nakamura
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Publication number: 20050008773Abstract: A method of manufacturing a magnetic recording medium facilitates preventing a film inflation from occurring in an environmental condition range between ?40° C. and 80° C. and an 80% relative humidity. The magnetic recording medium includes a plastic substrate and an undercoating layer on the plastic substrate. The undercoating layer is provided with a columnar structure, which prevents water (moisture) between the plastic substrate and the undercoating layer from aggregating and, therefore, the film inflation from occurring.Type: ApplicationFiled: August 11, 2004Publication date: January 13, 2005Applicant: Fuji Electric Co., Ltd.Inventors: Akira Iso, Hiroyuki Uwazumi, Takahiro Shimizu, Naoki Takizawa, Miyabi Nakamura