Patents by Inventor Makoto Imakawa
Makoto Imakawa 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: 20080268292Abstract: A magnetic recording medium is provided, comprising a substrate, a hexagonal close-packed seedlayer deposited over the substrate, a hexagonal close-packed underlayer deposited over the seedlayer, and a hexagonal close-packed recording layer deposited over the underlayer. The seedlayer is comprised of a ceramic. A method of manufacturing a magnetic recording medium is also provided, comprising the steps of sputtering a first sputter target to deposit a hexagonal close-packed seedlayer over a substrate, sputtering a second sputter target to deposit a hexagonal close-packed underlayer over the seedlayer, and sputtering a third sputter target to deposit a hexagonal close-packed magnetic recording layer over the underlayer. The seedlayer comprises a ceramic.Type: ApplicationFiled: April 26, 2007Publication date: October 30, 2008Applicant: HERAEUS, INC.Inventors: Anirban Das, Michael Gene Racine, Makoto Imakawa
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Publication number: 20080166596Abstract: A Re-based alloy material comprises >50 at. % Re and at least one alloying material selected from grain size refinement elements X which have an atomic radius larger or smaller than that of Re and a solid solubility <˜6 at. % in hcp Re at room or higher temperatures, and lattice matching elements Y which have an atomic radius larger or smaller than that of Re and form a solid solution in hcp Re at room or higher temperatures. The alloy material may further comprise at least one material selected from the group consisting of oxides, nitrides, and carbides. Targets comprising the Re-based alloy material are useful in sputter deposition of improved interlayers for obtaining optimally structured granular perpendicular magnetic recording layers.Type: ApplicationFiled: October 23, 2007Publication date: July 10, 2008Applicant: HERAEUS INC.Inventors: Anirban DAS, Michael Gene Racine, Makoto Imakawa, Steven Roger Kennedy, Rikhit Arora
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Patent number: 7166374Abstract: A magnetic recording medium comprising a non-ferromagnetic substrate and a magnetic recording film formed on the substrate with an underlayer interposed therebetween, wherein the magnetic recording film comprises a plurality of magnetic layers and an interlayer made of a material having a B2 crystal structure or an interlayer made of Ru, disposed between the adjacent magnetic layers.Type: GrantFiled: March 23, 2004Date of Patent: January 23, 2007Assignee: Komag, Inc.Inventors: Michinobu Suekane, Makoto Imakawa, Takehiko Hiruma
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Publication number: 20040180240Abstract: A magnetic recording medium comprising a non-ferromagnetic substrate and a magnetic recording film formed on the substrate with an underlayer interposed therebetween, wherein the magnetic recording film comprises a plurality of magnetic layers and an interlayer made of a material having a B2 crystal structure or an interlayer made of Ru, disposed between the adjacent magnetic layers.Type: ApplicationFiled: March 23, 2004Publication date: September 16, 2004Inventors: Michinobu Suekane, Makoto Imakawa, Takehiko Hiruma
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Patent number: 6743528Abstract: A magnetic recording medium comprising a non-ferromagnetic substrate and a magnetic recording film formed on the substrate with an underlayer interposed therebetween, wherein the magnetic recording film comprises a plurality of magnetic layers and an interlayer made of a material having a B2 crystal structure or an interlayer made of Ru, disposed between the adjacent magnetic layers.Type: GrantFiled: June 29, 2001Date of Patent: June 1, 2004Assignee: Komag, Inc.Inventors: Michinobu Suekane, Makoto Imakawa, Takehiko Hiruma
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Patent number: 6500567Abstract: In this invention, an ultra thin layer of CoCr alloy nucleation layer is sputtered at an extremely low deposition rate above a predominantly (200) oriented Cr film followed by a CoCrPt based alloy sputtered film at higher rates and moderate temperatures. This structure creates a media which has very high Hc, and excellent PW50, low noise and excellent low TNLD values. By using this technique, the CoCrPt magnetic film achieves excellent in-plane crystallographic orientation, and high Hc is achieved with minimal amount of Pt addition to the magnetic film. The method allows very fine grain structure of cobalt to be formed which contributes to good signal to noise ratio. A fine grain structure combined with chromium segregation between the grains improve the signal to noise ratio even more. A high degree of in-plane c-axis orientation is achieved in the cobalt layer which provides very high hysteresis loop squareness which helps to improve the OW and TNLD.Type: GrantFiled: October 3, 2000Date of Patent: December 31, 2002Assignee: Komag, Inc.Inventors: Gerardo Bertero, Charles Changqing Chen, Tu Chen, Tsutomu Yamashita, Makoto Imakawa, Michinobu Suekane
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Publication number: 20010044039Abstract: A magnetic recording medium comprising a non-ferromagnetic substrate and a magnetic recording film formed on the substrate with an underlayer interposed therebetween, wherein the magnetic recording film comprises a plurality of magnetic layers and an interlayer made of a material having a B2 crystal structure or an interlayer made of Ru, disposed between the adjacent magnetic layers.Type: ApplicationFiled: June 29, 2001Publication date: November 22, 2001Inventors: Michinobu Suekane, Makoto Imakawa, Takehiko Hiruma
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Patent number: 6309765Abstract: A magnetic recording medium comprising a non-ferromagnetic substrate and a magnetic recording layer formed on the substrate with an underlayer of Cr or a Cr alloy interposed therebetween, which has a seed layer between the substrate and the underlayer, wherein said seed layer is made of a material which contains at least 30 ppm of oxygen and which has a B2 crystal structure.Type: GrantFiled: March 4, 1999Date of Patent: October 30, 2001Assignee: Asahi Komag Co., Ltd.Inventors: Michinobu Suekane, Makoto Imakawa, Takehiko Hiruma, Kazuhiko Mitarai
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Patent number: 6261681Abstract: A magnetic recording medium comprising a non-ferromagnetic substrate and a magnetic recording film formed on the substrate with an underlayer interposed therebetween, wherein the magnetic recording film comprises a plurality of magnetic layers and an interlayer made of a material having a B2 crystal structure or an interlayer made of Ru, disposed between the adjacent magnetic layers.Type: GrantFiled: March 10, 1999Date of Patent: July 17, 2001Assignee: Asahi Komag Co., Ltd.Inventors: Michinobu Suekane, Makoto Imakawa, Takehiko Hiruma
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Patent number: 6150015Abstract: In this invention, an ultra thin layer of CoCr alloy nucleation layer is sputtered at an extremely low deposition rate above a predominantly (200) oriented Cr film followed by a CoCrPt based alloy sputtered film at higher rates and moderate temperatures. This structure creates a media which has very high Hc, and excellent PW50, low noise and excellent low TNLD values. By using this technique, the CoCrPt magnetic film achieves excellent in-plane crystallographic orientation, and high Hc is achieved with minimal amount of Pt addition to the magnetic film. The method allows very fine grain structure of cobalt to be formed which contributes to good signal to noise ratio. A fine grain structure combined with chromium segregation between the grains improve the signal to noise ratio even more. A high degree of in-plane c-axis orientation is achieved in the cobalt layer which provides very high hysteresis loop squareness which helps to improve the OW and TNLD.Type: GrantFiled: December 4, 1997Date of Patent: November 21, 2000Assignee: Komag, IncorporatedInventors: Gerardo Bertero, Charles Changqing Chen, Tu Chen, Tsutomu Yamashita, Makoto Imakawa, Michinobu Suekane
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Patent number: 5846648Abstract: A magnetic recording medium is provided with a structured nucleation layer. The structured nucleation layer comprises a fine-grained seed layer and an intermediate layer. The seed layer (e.g., NiAl, Ti, Cr--Cu, etc.) serves as a template for fine grained-growth of the intermediate layer. The intermediate (e.g., Cr, etc.) layer has preferred crystal textures and an appropriate lattice match to a subsequently deposited magnetic recording layer to allow epitaxial growth of the magnetic recording layer. The intermediate layer provides morphology and orientation to the magnetic recording layer. The magnetic recording layer (e.g., Co-alloy) includes a material which segregates to the alloy grain boundaries to isolate the grains thereof. Each grain of the magnetic recording layer is predominantly a single crystal of small size and uniformly spaced from adjacent grains. The easy axis of the magnetic recording material is predominantly in the plane of the disk, with a random in-plane orientation.Type: GrantFiled: February 18, 1997Date of Patent: December 8, 1998Assignee: Komag, Inc.Inventors: Tu Chen, Michinobu Suekane, Makoto Imakawa, Kazuhiko Mitarai
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Patent number: 5022919Abstract: A complex boride cermet having high strength and high toughness, which comprises a hard phase composed mainly of a boride of (Mo.sub.1-x W.sub.x).sub.2 NiB.sub.2 formed by substituting a part of Mo of Mo.sub.2 NiB.sub.2 by W, and a matrix alloy phase composed mainly of Ni and containing Mo, and a complex boride cermet comprising a hard phase composed mainly of Mo.sub.2 NiB.sub.2 or (Mo.sub.1-x W.sub.x).sub.2 NiB.sub.2 and a matrix of an alloy phase composed mainly of Ni and containing Mo, which is characterized in that carbon or/and nitrogen, and optionally at least one metal selected from the metals of Groups 4B and 5B and Cr, are incorporated to further improve the strength and toughness. Such complex boride cermet has high strength and high toughness and maintains such properties even at elevated temperatures of from 600.degree. to 900.degree. C.Type: GrantFiled: May 16, 1989Date of Patent: June 11, 1991Assignee: Asahi Glass Company Ltd.Inventors: Yasuo Shinozaki, Noritoshi Horie, Kazuo Hamashima, Makoto Imakawa
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Patent number: 4671822Abstract: A ZrB.sub.2 -containing sintered cermet comprising zirconium diboride partially substituted by at least one member selected from the group consisting of chromium boride, molybdenum boride and tungsten boride, and a binding component containing at least one member selected from the group consisting of metals of Group VIII of the periodic table.Type: GrantFiled: June 4, 1986Date of Patent: June 9, 1987Assignee: Asahi Glass Company, Ltd.Inventors: Kazuo Hamashima, Makoto Imakawa, Yukinori Kutsukake