Patents by Inventor Tetsuya Kanbe
Tetsuya Kanbe 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: 11244700Abstract: A magnetic recording medium includes a substrate, an underlayer provided on the substrate, and a magnetic layer provided on the underlayer and having a L10 structure and a (001) orientation. The magnetic layer has a granular structure in which an organic compound having a methylene skeleton or a methine skeleton is arranged at grain boundaries of magnetic grains.Type: GrantFiled: October 24, 2018Date of Patent: February 8, 2022Assignee: SHOWA DENKO K.K.Inventors: Katsumi Murofushi, Yoshitaka Ishibashi, Takayuki Fukushima, Kazuya Niwa, Lei Zhang, Yuji Murakami, Hisato Shibata, Takehiro Yamaguchi, Chen Xu, Tetsuya Kanbe, Tomoo Shige
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Patent number: 11037591Abstract: A heat-assisted magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having an L10 structure, wherein the underlayer includes, from the substrate side, a bcc underlayer including a substance having a bcc structure, a first oxide layer that is in contact with the bcc underlayer, and a second oxide layer that is in contact with the magnetic layer. The bcc underlayer, the first oxide layer, and the second oxide layer are stacked in the recited order. The first oxide layer and the second oxide layer include magnesium oxide, and the second oxide layer further includes one or more compounds selected from the group consisting of vanadium oxide, vanadium nitride, and vanadium carbide.Type: GrantFiled: June 6, 2019Date of Patent: June 15, 2021Assignee: SHOWA DENKO K.K.Inventors: Lei Zhang, Chen Xu, Takayuki Fukushima, Kazuya Niwa, Tetsuya Kanbe, Hisato Shibata, Takehiro Yamaguchi, Tomoo Shige
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Patent number: 10978103Abstract: A magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having a L10 structure and a (001) orientation, wherein the substrate, the underlayer, and the magnetic layer are stacked in the recited order, and wherein the magnetic layer has a granular structure and includes a carbon hydride, a boron hydride, or a boron nitride hydride.Type: GrantFiled: May 9, 2019Date of Patent: April 13, 2021Assignee: SHOWA DENKO K.K.Inventors: Takayuki Fukushima, Kazuya Niwa, Lei Zhang, Hisato Shibata, Takehiro Yamaguchi, Chen Xu, Tetsuya Kanbe, Tomoo Shige
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Patent number: 10803895Abstract: A magnetic recording medium includes: a substrate; a first underlayer; a second underlayer; and a magnetic layer including an alloy having a L10 type crystal structure with a (001) orientation. The substrate, the first underlayer, the second underlayer, and the magnetic layer are stacked in this order. The first underlayer is a crystalline layer that includes Mo as a main component. The second underlayer is a crystalline layer that includes a material containing Mo as a main component and that includes an oxide. The content of the oxide in the second underlayer is in a range of from 2 mol % to 30 mol %. The oxide is an oxide of one or more kinds of elements selected from a group consisting of Cr, Mo, Nb, Ta, V, and W.Type: GrantFiled: January 2, 2018Date of Patent: October 13, 2020Assignee: SHOWA DENKO K.K.Inventors: Takayuki Fukushima, Haruhisa Ohashi, Lei Zhang, Yuji Murakami, Hisato Shibata, Takehiro Yamaguchi, Tetsuya Kanbe
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Patent number: 10706884Abstract: A magnetic recording medium includes: a substrate; a first underlayer; a second underlayer; and a magnetic layer including an alloy having a L10 type crystal structure with a (001) orientation. The substrate, the first underlayer the second underlayer, and the magnetic layer are stacked in this order. The first underlayer is a crystalline layer that includes W as a main component. The second underlayer is a crystalline layer that includes a material containing W as a main component and that includes an oxide. The content of the oxide in the second underlayer is in a range of from 2 mol % to 30 mol %. The oxide is an oxide of one or more kinds of elements selected from a group consisting of Cr, Mo, Nb, Ta, V, and W.Type: GrantFiled: December 21, 2017Date of Patent: July 7, 2020Assignee: SHOWA DENKO K.K.Inventors: Takayuki Fukushima, Haruhisa Ohashi, Lei Zhang, Yuji Murakami, Hisato Shibata, Takehiro Yamaguchi, Tetsuya Kanbe
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Patent number: 10699737Abstract: A magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having a L10 type crystal structure whose plane orientation is (001). The substrate, the underlayer, and the magnetic layer are stacked in this order. The underlayer includes a first underlayer. The first underlayer is a crystalline layer that includes a material containing Al, Ag, Cu, W, or Mo as a main component element and includes an oxide of the main component element, a content of the oxide of the main component element in the first underlayer being in a range of from 2 mol % to 30 mol %.Type: GrantFiled: January 2, 2018Date of Patent: June 30, 2020Assignee: SHOWA DENKO K.K.Inventors: Takayuki Fukushima, Haruhisa Ohashi, Lei Zhang, Yuji Murakami, Hisato Shibata, Takehiro Yamaguchi, Tetsuya Kanbe
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Patent number: 10643649Abstract: A heat-assisted magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having an L10 structure. The substrate, the underlayer, and the magnetic layer are stacked in the recited order. The underlayer includes a first underlayer. The first underlayer includes magnesium oxide and one or more compounds selected from the group consisting of vanadium oxide, zinc oxide, tin oxide, vanadium nitride, and vanadium carbide, and a total content of the one or more compounds is in a range of 45 mol % to 70 mol %.Type: GrantFiled: June 21, 2019Date of Patent: May 5, 2020Assignees: SHOWA DENKO K.K., TOHOKU UNIVERSITYInventors: Shin Saito, Takayuki Fukushima, Lei Zhang, Hisato Shibata, Takehiro Yamaguchi, Chen Xu, Tetsuya Kanbe, Tomoo Shige, Kazuya Niwa, Atsushi Hashimoto
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Patent number: 10614849Abstract: A heat-assisted magnetic recording medium includes a substrate, an underlayer, and a magnetic layer including an alloy having a L10 crystal structure and first and second layers, arranged in this order. Each of the first and second layers has a granular structure including C, SiO2, and BN at grain boundaries. Vol % of the grain boundaries in each of the first and second layers is 25 to 45 vol %. Vol % of C in the first layer is 5 to 22 vol %, and a volume ratio of SiO2 with respect to BN in each of the first and second layers is 0.25 to 3.5. Vol % of SiO2 in the second layer is greater than that of the first layer by 5 vol % or more. Vol % of BN in the second layer is smaller than that in the first layer by 2 vol % or more.Type: GrantFiled: July 23, 2019Date of Patent: April 7, 2020Assignee: SHOWA DENKO K.K.Inventors: Takayuki Fukushima, Koji Take, Hisato Shibata, Takehiro Yamaguchi, Tomoo Shige, Lei Zhang, Chen Xu, Yuji Umemoto, Hiroshi Koyanagi, Kazuya Niwa, Tetsuya Kanbe
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Patent number: 10553242Abstract: A heat-assisted magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer that is (001)-oriented. In the magnetic layer, a first magnetic layer and a second magnetic layer are stacked in this order from the underlayer side. The first magnetic layer and the second magnetic layer include an alloy having an L10 structure. The second magnetic layer includes a ferrite at grain boundaries of magnetic grains. The ferrite is one or more kinds selected from the group consisting of NiFe2O4, MgFe2O4, MnFe2O4, CuFe2O4, ZnFe2O3, CoFe2O4, BaFe2O4, SrFe2O4, and Fe3O4. A Curie temperature of the magnetic grains is lower than a Curie temperature of the ferrite.Type: GrantFiled: June 19, 2019Date of Patent: February 4, 2020Assignee: SHOWA DENKO K.K.Inventors: Lei Zhang, Takayuki Fukushima, Chen Xu, Kazuya Niwa, Hisato Shibata, Takehiro Yamaguchi, Tetsuya Kanbe, Tomoo Shige
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Patent number: 10360936Abstract: The invention provides a magnetic recording medium with an excellent signal-to-noise ratio during reading by reducing the noise produced during writing of data onto the magnetic recording medium, and increasing the signal level. The assisted magnetic recording medium according to one embodiment comprising a substrate, a base layer, and a magnetic layer composed mainly of an alloy with an L10-type crystal structure, the assisted magnetic recording medium having a pinning layer in contact with the magnetic layer, and the pinning layer including Co or an alloy composed mainly of Co.Type: GrantFiled: January 31, 2018Date of Patent: July 23, 2019Assignee: SHOWA DENKO K.K.Inventors: Kazuya Niwa, Tetsuya Kanbe, Yuji Murakami, Lei Zhang, Hisato Shibata, Takayuki Fukushima, Satoru Nakajima, Takehiro Yamaguchi
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Patent number: 10283154Abstract: A magnetic recording medium includes a substrate, a barrier layer, a crystal grain size control layer, and a magnetic layer that are arranged in this order. The barrier layer includes at least one of oxides, nitrides, and carbides, and the crystal grain size control layer is a crystalline layer including Ag and having an average thickness in a range of 0.1 nm to 1 nm. The barrier layer makes contact with the crystal grain size control layer, and the magnetic layer includes an alloy having a L10 crystal structure and a (001) face orientation.Type: GrantFiled: May 15, 2018Date of Patent: May 7, 2019Assignees: SHOWA DENKO K.K., TOHOKU UNIVERSITYInventors: Shintaro Hinata, Shin Saito, Takayuki Fukushima, Haruhisa Ohashi, Kazuya Niwa, Lei Zhang, Yuji Murakami, Hisato Shibata, Takehiro Yamaguchi, Tetsuya Kanbe, Tomoo Shige
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Patent number: 10127939Abstract: A magnetic recording medium includes a substrate, a first heat sink layer, a barrier layer, a second heat sink layer, and a magnetic layer that are successively stacked. The magnetic layer is made of a material including a first main component that is an alloy having a L10 crystal structure and a content of 50 at % or higher, or content of 50 mol % or higher. The barrier layer is made of a material including a second main component that is one of an oxide, a nitride, and a carbide having a content of 50 at % or higher, or content of 50 mol % or higher.Type: GrantFiled: January 11, 2018Date of Patent: November 13, 2018Assignee: SHOWA DENKO K.K.Inventors: Kazuya Niwa, Lei Zhang, Yuji Murakami, Hisato Shibata, Takayuki Fukushima, Takehiro Yamaguchi, Tetsuya Kanbe
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Patent number: 10008220Abstract: A magnetic recording medium includes a substrate; a lower base layer formed on the substrate; and a (001) oriented L10 magnetic layer formed on the lower base layer and including a first magnetic layer formed on the lower base layer and having a granular structure of magnetic grains and a grain boundary portion, the grain boundary portion containing C, and a second magnetic layer formed on the first magnetic layer and having a granular structure of magnetic grains and a grain boundary portion, the grain boundary portion containing oxide or nitride, the second magnetic layer further containing one or more elements selected from a group consisting of Mg, Ni, Zn, Ge, Pd, Sn, Ag, Re, Au and Pb as an additive.Type: GrantFiled: May 16, 2017Date of Patent: June 26, 2018Assignee: SHOWA DENKO K.K.Inventors: Takayuki Fukushima, Yuji Murakami, Tetsuya Kanbe, Lei Zhang, Kazuya Niwa, Hisato Shibata
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Patent number: 9934810Abstract: A magnetic recording medium includes a substrate, multiple underlayers formed on the substrate, and a magnetic layer formed on the multiple underlayers. A main component of the magnetic layer is an alloy having a L10 structure. At least one of the multiple underlayers is a crystalline underlayer containing W. The W is a main component of the crystalline underlayer. The crystalline underlayer further contains 1 mol % or more to 20 mol % or less of one or more kinds of elements selected from B, Si, and C. A barrier layer including a material having a NaCl structure is formed between the crystalline underlayer and the magnetic layer.Type: GrantFiled: March 20, 2014Date of Patent: April 3, 2018Assignee: SHOWA DENKO K.K.Inventors: Lei Zhang, Tetsuya Kanbe, Yuji Murakami, Kazuya Niwa
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Patent number: 9818441Abstract: Disclosed is a thermally assisted magnetic recording medium comprising a substrate, a plurality of underlayers formed on the substrate, and a magnetic layer which is formed on the underlayers and predominantly comprised of an alloy having a L10 structure, characterized in that at least one of the underlayers is predominantly comprised of MgO and comprises at least one oxide selected from SiO2, TiO2, Cr2O3, Al2O3, Ta2O5, ZrO2, Y2O3, CeO2, MnO, TiO and ZnO. The thermally assisted magnetic recording medium has a magnetic layer comprised of fine magnetic crystal grains, exhibiting a sufficiently weak exchange coupling between magnetic grains, and having a minimized coercive force dispersion.Type: GrantFiled: February 3, 2011Date of Patent: November 14, 2017Assignee: SHOWA DENKO K.K.Inventors: Tetsuya Kanbe, Atsushi Hashimoto, Takayuki Fukushima
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Patent number: 9384772Abstract: A magnetic recording medium includes a substrate, a magnetic layer including an alloy having a L10 type crystal structure as a main component thereof, and a plurality of underlayers arranged between the substrate and the magnetic layer. The plurality of underlayers include a first underlayer including two or more elements selected from a group consisting of Ta, Nb, Ti, and V, and one or more elements selected from a group consisting of W and Mo, and a second underlayer including MgO.Type: GrantFiled: July 17, 2014Date of Patent: July 5, 2016Assignee: SHOWA DENKO K.K.Inventors: Lei Zhang, Tetsuya Kanbe, Yuji Murakami, Kazuya Niwa
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Patent number: 9361924Abstract: A thermally-assisted magnetic recording medium or a microwave-assisted magnetic recording medium includes: an orientation control layer (104) that is formed on a substrate (101); an underlayer (10) that is formed on the orientation control layer (104); and a magnetic layer (108) that is formed on the underlayer (10) and contains an alloy having an L10 type crystal structure as a main component, in which the underlayer (10) includes an MgO underlayer (107) that contains MgO and has a (100) orientation and a nitride underlayer (106) that contains at least one nitride selected from the group consisting of TaN, NbN, and HfN and has a (100) orientation.Type: GrantFiled: May 10, 2013Date of Patent: June 7, 2016Assignee: SHOWA DENKO K.K.Inventors: Kazuya Niwa, Tetsuya Kanbe, Yuji Murakami, Lei Zhang
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Patent number: 9251834Abstract: A magnetic recording medium includes a substrate, a magnetic layer including an alloy having an L10 type crystal structure as a main component thereof, and a plurality of underlayers arranged between the substrate and the magnetic layer. The plurality of underlayers include at least one crystalline underlayer which has a (100) orientation, and includes W as a main component thereof and one or more kinds of elements selected from a group consisting of Fe, Ni, Co, Hf, Zr, Y, Be, Ce, La, and Sc.Type: GrantFiled: October 1, 2014Date of Patent: February 2, 2016Assignee: SHOWA DENKO K.K.Inventors: Lei Zhang, Tetsuya Kanbe, Yuji Murakami, Kazuya Niwa
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Patent number: 9245567Abstract: A magnetic recording medium includes a substrate, a magnetic layer including a FePt alloy having a L10 type structure, and a plurality of underlayers arranged between the substrate and the magnetic layer, wherein at least one of the plurality of underlayers includes TiO2.Type: GrantFiled: June 16, 2014Date of Patent: January 26, 2016Assignee: SHOWA DENKO K.K.Inventors: Tetsuya Kanbe, Kazuya Niwa, Yuji Murakami, Lei Zhang
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Patent number: 9230588Abstract: A magnetic recording medium includes a substrate, a magnetic layer including an alloy having an L10 type crystal structure as a main component thereof, a plurality of underlayers arranged between the substrate and the magnetic layer, and a barrier layer made of a material having an NaCl structure. The plurality of underlayers include at least one crystalline underlayer including Mo as a main component thereof, and at least one of Si and C in a range of 1 mol % to 20 mol % and an oxide in a range of 1 vol % to 50 vol %. The barrier layer is provided between the magnetic layer and the at least one crystalline underlayer including Mo.Type: GrantFiled: July 9, 2014Date of Patent: January 5, 2016Assignee: SHOWA DENKO K.K.Inventors: Lei Zhang, Tetsuya Kanbe, Yuji Murakami, Kazuya Niwa