Ferromagnetic (elemental Or Alloy) Particles Patents (Class 428/842.3)
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Patent number: 10902875Abstract: Provided is a magnetic tape cartridge of a single reel type in which a magnetic tape is wound around a reel, in which the magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, a tape thickness is equal to or smaller than 5.2 ?m, a tape width difference (B?A) between a tape width A at a position of 10 m±1 m from a tape outer end and a tape width B at a position of 50 m±1 m from a tape inner end is 2.4 ?m to 12.0 ?m, and the tape width A and the tape width B are values measured 100 days from the date of magnetic tape cartridge manufacture.Type: GrantFiled: April 15, 2020Date of Patent: January 26, 2021Assignee: FUJIFILM CorporationInventors: Yusuke Kagawa, Norihito Kasada, Yuto Murata
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Patent number: 10781352Abstract: A hexagonal boron nitride (hBN) powder containing an aggregate of primary particles of hBN, in which the powder has a primary particle size of less than 10 ?m, a ratio of an average longer diameter (L1) to an average thickness (d1) of the primary particles, [L1/d1], of 5.0 or more and 20 or less, and a BET specific surface area of less than 10 m2/g. The powder has one maximum peak in a range of a particle size of 45 ?m or more and 150 ?m or less in a particle size distribution curve of a hexagonal boron nitride powder classified to have a particle size of 45 ?m or more and 106 ?m or less, and has a decrease rate of the maximum peak of 10% or more and less than 40%.Type: GrantFiled: August 19, 2016Date of Patent: September 22, 2020Assignee: SHOWA DENKO K.K.Inventors: Yuki Otsuka, Masaru Fukasawa
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Patent number: 10663649Abstract: Provided are a light guide plate and a method for preparing the same, a backlight module, and a display device. The light guide plate includes a substrate having a first surface and a second surface; and a dot layer arranged on the second surface, in which the dot layer includes magnetic particles, and the first surface is a light exiting surface of the light guide plate.Type: GrantFiled: May 17, 2019Date of Patent: May 26, 2020Assignees: HEFEI BOE DISPLAY LIGHTING CO., LTD., BOE TECHNOLOGY GROUP CO., LTD.Inventors: Qiping Zhang, Yeshun Xu, Xing Wang, Xiang Liu, Zungan Ling
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Patent number: 10497384Abstract: A magnetic tape device includes a magnetic tape; and a Tunneling Magnetoresistive (PAR) head as a reproducing head, in which the center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, the logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and ?SFD in a longitudinal direction of the magnetic tape calculated by Expression 1: ?SFD=SFD25° C.?SFD?190° C. is equal to or smaller than 0.50, wherein, in Expression 1, the SFD25° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD?190° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of ?190° C.Type: GrantFiled: February 20, 2018Date of Patent: December 3, 2019Assignee: FUJIFILM CorporationInventors: Norihito Kasada, Eiki Ozawa
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Publication number: 20150093599Abstract: The magnetic coating composition for a magnetic recording medium comprises: (A) a compound denoted by formula (1) having a weight average molecular weight of equal to or less than 20,000: (A1-R2—S)n-R1—(P1)m ??(1) wherein, in formula (1), R1 denotes an organic connecting group with a valence of (m+n); R2 denotes a single bond or divalent organic connecting group; A1 denotes a functional group selected from the group consisting of an acidic group, a basic group, and a hydroxyl group; m denotes an integer ranging from 1 to 8 and n denotes an integer ranging from 1 to 9, with m+n ranging from 3 to 10; each of n instances of A1 and R2 can be independently different or identical; P1 denotes a polymer backbone; and m instances of P1 can be identical or different; (B) binder; (C) ferromagnetic powder; and (D) solvent.Type: ApplicationFiled: September 26, 2014Publication date: April 2, 2015Applicant: FUJIFILM CORPORATIONInventor: Reiko FUKAGAWA
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Publication number: 20150093600Abstract: An aspect of the present invention relates to ferromagnetic hexagonal ferrite powder, the average particle size of which is equal to or less than 20 nm, and which comprises, on a particle number basis, equal to or more than 50% of ellipsoid hexagonal ferrite powders satisfying relation (1): 1.2<major axis length/minor axis length<2.0 . . . (1).Type: ApplicationFiled: September 29, 2014Publication date: April 2, 2015Applicant: FUJIFILM CORPORATIONInventor: Yoichi HOSOYA
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Publication number: 20140295214Abstract: Hexagonal ferrite magnetic particles have an activation volume ranging from 1,000 nm3 to 1,500 nm3, and ?E10%/kT, thermal stability at 10% magnetization reversal, is equal to or greater than 40.Type: ApplicationFiled: March 25, 2014Publication date: October 2, 2014Applicant: FUJIFILM CORPORATIONInventors: Toshio TADA, Hiroyuki SUZUKI, Osamu SHIMIZU
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Publication number: 20140255728Abstract: An aspect of the present invention relates to a magnetic recording medium, which comprises magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the ferromagnetic hexagonal ferrite powder has an activation volume ranging from 800 nm3 to 1,300 nm3, and 1 percent to 50 percent of particles constituting the ferromagnetic hexagonal ferrite powder are ferromagnetic hexagonal ferrite particles, each of which has an indentation with a depth of equal to or more than 1/10 of an equivalent projected circle diameter of the ferromagnetic hexagonal ferrite particle.Type: ApplicationFiled: March 7, 2014Publication date: September 11, 2014Applicant: FUJIFILM CORPORATIONInventor: Masashi SHIRATA
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Patent number: 8815393Abstract: The present invention refer to a innovative process for obtaining nanoparticulate magnetic ferrites, at low temperatures, simple or mixed, functionalized by organic molecules, for dispersion of these nanoparticles in polar or nonpolar media, and the same particles dispersed in a liquid medium, also known as ferrofluids. The present invention enables obtaining both simple ferrites (MFe2O4 or MFe12O19) and mixed ferrites (Nx M(1-x) Fe2O4 or N1-Y Mx+Y Fe(2-x) O4; as example) where M and N can be metals, such as Sm, La, Bi, Ba, Mo, Sr, Ni, Fe, Mn, Cr, etc., through the coprecipitation method, functionalized by organic molecules containing carboxylic groups, which are polymers, or long chain acids or short chain acids, containing mono, di or tricarboxylic groups and/or alcohols, whose dispersion in polar or nonpolar media is improved. The present invention enables also obtaining ferrofluids, through the mixture of the obtained magnetic particles with an appropriate liquid carrier.Type: GrantFiled: May 3, 2011Date of Patent: August 26, 2014Assignee: Nanum Nanotecnologia S/AInventors: Jose Fernando Contadini, Tarik Della Santina Mohallem, Taiane Guedes Fonseca De Souza
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Patent number: 8802234Abstract: A composite nanoparticle, for example a nanoparticle containing one or a plurality of cores embedded in another material. A composite nanoparticle can be formed by a one step process that includes: ejecting material from a bulk target material using physical energy source, with the bulk target material disposed in a liquid. Composite nanoparticles are formed by cooling at least a portion of the ejected material in the liquid. The composite fine particles may then be collected from the liquid. A product that includes composite fine particles may be formed with laser ablation, and ultrashort laser ablation may be utilized so as to preserve composite nanoparticle stoichiometry. For applications of the composite fine particles, optical properties and/or magnetic properties may be exploited for various applications.Type: GrantFiled: January 3, 2011Date of Patent: August 12, 2014Assignee: Imra America, Inc.Inventors: Yong Che, Makoto Murakami, Wei Guo
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Patent number: 8742518Abstract: A magnetic tunnel junction device includes a reference magnetic layer and a magnetic free layer including first and second magnetic elements that are magnetically exchange coupled. The magnetic exchange coupling between the first and second magnetic elements is configured to achieve a switching current distribution less than about 200% and a long term thermal stability criterion of greater than about 60 kBT.Type: GrantFiled: March 31, 2011Date of Patent: June 3, 2014Assignee: Seagate Technology LLCInventors: Xiaobin Wang, Kaizhong Gao
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Patent number: 8475922Abstract: According to one embodiment, there is provided a nanoparticle composite material, including nanoparticle aggregates in a shape having an average height of 20 nm or more and 2 ?m or less and having an average aspect ratio of 5 or more, the nanoparticle aggregates including metal nanoparticles having an average diameter of 1 nm or more and 20 nm or less and containing at least one magnetic metals selected from the group consisting of Fe, Co and Ni and binder existing between the nanoparticle aggregates.Type: GrantFiled: September 23, 2010Date of Patent: July 2, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Tomohiro Suetsuna, Seiichi Suenaga, Tomoko Eguchi, Koichi Harada, Maki Yonetsu, Yasuyuki Hotta, Toshihide Takahashi
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Publication number: 20130084470Abstract: An aspect of the present invention relates to a magnetic recording medium comprising a magnetic layer containing a ferromagnetic powder and a binder on a nonmagnetic support, wherein the ferromagnetic powder has a hexagonal ferrite structure, the magnetic layer comprises a coefficient of friction-lowering component in the form of nonmagnetic inorganic particles, and a compound in which a substituent selected from the group consisting of a hydroxyl group and a carboxyl group is directly substituted on an aromatic ring.Type: ApplicationFiled: October 1, 2012Publication date: April 4, 2013Applicant: FUJIFILM CORPORATIONInventor: FUJIFILM CORPORATION
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Publication number: 20120177950Abstract: An aspect of the present invention relates to a binder resin composition for a magnetic recording medium, which comprises a vinyl chloride resin containing a radiation-curable functional group, and a methacrylate compound denoted by formula (A): in an amount of equal to or more than 0.3 weight percent but equal to or less than 10 weight percent relative to a content of the vinyl chloride resin.Type: ApplicationFiled: January 11, 2012Publication date: July 12, 2012Applicant: FUJIFILM CORPORATIONInventor: Kazufumi OMURA
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Patent number: 7910214Abstract: The present invention relates to a molded ferrite sheet having opposing surfaces and a thickness in a range of 30 ?m to 430 ?m, at least one surface of said opposing surfaces having the following surface roughness characteristics (a) to (c): (a) a center line average roughness is in a range of 170 nm to 800 nm, (b) a maximum height is in a range of 3 ?m to 10 ?m, and (c) an area occupancy rate of cross-sectional area taken along a horizontal plane at a depth of 50% of the maximum height in a square of side 100 ?m is in a range of 10 to 80%.Type: GrantFiled: March 6, 2008Date of Patent: March 22, 2011Assignee: Toda Kogyo CorporationInventors: Tetsuya Kimura, Tomohiro Dote, Kazumi Yamamoto, Takanori Doi, Yoji Okano
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Patent number: 7737304Abstract: A compound represented by the Formula (1) below is provided: wherein X denotes a divalent linking group, R1 and R2 independently denote an alkyl group having 3 or more carbons and having at least one hydroxy group or an aralkyl group having 8 or more carbons and having at least one hydroxy group, the alkyl group and aralkyl group may have a substituent, and M denotes a hydrogen atom or a cation. There is also provided a polyurethane resin obtained by polymerization of a polyisocyanate and a polyol that includes the compound. There is also provided a magnetic recording medium that includes a non-magnetic support and, above the support, at least one magnetic layer including a ferromagnetic powder dispersed in a binder that includes the polyurethane resin.Type: GrantFiled: September 23, 2008Date of Patent: June 15, 2010Assignee: FUJIFILM CorporationInventors: Kazufumi Omura, Masahiko Mori, Katsumi Araki, Masataka Yoshizawa
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Patent number: 7737305Abstract: A compound represented by the Formula (1) below is provided: wherein X denotes a divalent linking group, R1 and R2 independently denote an alkyl group having 3 or more carbons and having at least one hydroxy group or an aralkyl group having 8 or more carbons and having at least one hydroxy group, the alkyl group and aralkyl group may have a substituent, and M denotes a hydrogen atom or a cation. There is also provided a polyurethane resin obtained by polymerization of a polyisocyanate and a polyol that includes the compound. There is also provided a magnetic recording medium that includes a non-magnetic support and, above the support, at least one magnetic layer including a ferromagnetic powder dispersed in a binder that includes the polyurethane resin.Type: GrantFiled: June 24, 2009Date of Patent: June 15, 2010Assignee: FUJIFILM CorporationInventors: Kazufumi Omura, Masahiko Mori, Katsumi Araki, Masataka Yoshizawa
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Patent number: 7674930Abstract: To prepare a polyester polyol in which a lactone is ring-opening addition polymerized with the compound represented by formula (I). (wherein each of A1 and A2 represents an alkylene group having not less than 2 carbon atoms, A3 represents an alkylene group, X represents a cationic component, and each of n and m represents an integer of not less than 1.) The polyester polyol has a high hydrophilic group and high solubility in a solvent (particularly, a low-boiling organic solvent used in the production of a polyurethane) and can design an aqueous polyurethane desirably and produce the aqueous polyurethane.Type: GrantFiled: August 3, 2006Date of Patent: March 9, 2010Assignee: Daicel Chemical Industries, Ltd.Inventors: Kazunori Nakao, Nobuyuki Watanabe
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Patent number: 7563522Abstract: The present invention provides a magnetic recording medium comprising a magnetic layer with excellent surface smoothness, which comprises a thin film magnetic layer of thickness in a range from 0.03 to 0.30 ?m that is ideal for short wavelength recording, and displays superior electromagnetic conversion characteristics. The magnetic recording medium comprises a magnetic layer containing at least a ferromagnetic powder and a binder resin on one surface of a non-magnetic support, wherein the thickness of the magnetic layer is within a range from 0.03 to 0.30 ?m, and the number of concavities with a depth of 30 nm or greater in the surface of the magnetic layer is 5 per 1 cm2 of surface area or less. Preferably, the value of the average depth Rv6 of the surface of the magnetic layer, as measured by a contact type surface roughness meter, is 12 nm or less.Type: GrantFiled: November 2, 2006Date of Patent: July 21, 2009Assignee: TDK CorporationInventors: Naoto Yajima, Takayoshi Kuwajima, Akihiko Seki, Hiroyuki Yamada, Kenichi Kitamura
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Publication number: 20090092857Abstract: The present invention relates to a method of manufacturing a magnetic recording medium comprising coating a magnetic layer coating liquid comprising a ferromagnetic hexagonal ferrite powder and a binder to form a coating film, subjecting the coating film to orientation processing while the coating film is still wet, and drying the coating film to form a magnetic layer. The magnetic layer coating liquid is prepared by subjecting a ferromagnetic hexagonal ferrite powder with an average plate diameter of 10 to 50 nm to a dry comminution step, subjecting the ferromagnetic hexagonal ferrite powder to a first dispersion step together with a binder to prepare a dispersion liquid, and sequentially subjecting the dispersion liquid obtained to a second dispersion step and a filtering step. The dispersion liquid obtained by the first dispersion step comprises a dry solid component in an amount, as measured after filtration, of 15 percent or less.Type: ApplicationFiled: October 2, 2008Publication date: April 9, 2009Applicant: FUJIFILM CorporationInventors: Ayako MATSUMOTO, Satoshi Matsubaguchi
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Publication number: 20090087687Abstract: A compound represented by the Formula below is provided. (in Formula (1), X denotes a divalent linking group, R1 and R2 independently denote an alkyl group having 3 or more carbons and having at least one hydroxy group or an aralkyl group having 8 or more carbons and having at least one hydroxy group, the alkyl group and aralkyl group may have a substituent, and M denotes a hydrogen atom or a cation). There is also provided a polyurethane resin obtained by polymerization of a polyisocyanate and a polyol that includes the compound. There is also provided a magnetic recording medium that includes a non-magnetic support and, above the support, at least one magnetic layer including a ferromagnetic powder dispersed in a binder that includes the polyurethane resin.Type: ApplicationFiled: September 23, 2008Publication date: April 2, 2009Applicant: FUJIFILM CorporationInventors: Kazufumi OMURA, Masahiko Mori, Katsumi Araki, Masataka Yoshizawa
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Patent number: 7407705Abstract: A magnetic powder composed primarily of Fe that has been surface-treated with a silane coupling agent, which magnetic powder is characterized in that it contains Co such that Co/Fe expressed in atomic percent is 20-50 at. %, Al such that Al/Fe expressed in atomic percent is 5-30 at. %, and one or more rare earth elements R (including Y) such that R/Fe expressed in atomic percent is 4-20 at. %, and has average particle diameter of smaller than 80 nm, TAP density of 0.7 g/cm3 or greater, ignition point of 165° C. or higher, and oxygen content of 26 wt % or less.Type: GrantFiled: May 7, 2004Date of Patent: August 5, 2008Assignee: Dowa Electronics Materials Co., Ltd.Inventor: Kimitaka Sato
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Patent number: 7405086Abstract: A manganese-implanted silicon substrate exhibits ferromagnetism and a Curie temperature above room temperature when magnetized. The implant is done at a temperature of between about 250 C and about 800 C, while the manganese concentration is between about 0.01 atomic percent and 10 atomic percent. The silicon substrate can be p- or n-type with a doping concentration between 1015 and 1021 cm?3. Annealing may be done to increase the saturation magnetization.Type: GrantFiled: March 22, 2005Date of Patent: July 29, 2008Assignee: The Research Foundation of State University of New YorkInventors: Vincent Patrick LaBella, Martin Bolduc, Chaffra Adeyandju Awo-Affouda, Mengbing Huang
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Patent number: 7402349Abstract: The invention is directed to a magnetic thick film composition comprising particles of permanent magnetic materials dispersed in organic medium wherein the medium comprises a polymer selected from polyurethane, phenoxy and mixtures thereof, and organic solvent.Type: GrantFiled: August 29, 2006Date of Patent: July 22, 2008Assignee: E. I. du Pont de Nemours and CompanyInventor: John Graeme Pepin
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Publication number: 20070231606Abstract: A magnetic recording medium comprising a substrate and a magnetic layer containing ferromagnetic metal powder and a binder, wherein the ferromagnetic metal powder contains iron, cobalt and form 2 to 20 atom % of yttrium based on a total of iron and cobalt contained in the ferromagnetic metal powder and has an average length of 50 nm or smaller, and the magnetic recording medium has a test value of at least 100 passes in a magnetoresistive head resistance reduction test performed as defined herein.Type: ApplicationFiled: April 2, 2007Publication date: October 4, 2007Applicant: FUJIFILM CorporationInventor: Kazuko Hanai
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Publication number: 20070224458Abstract: The present invention provides a magnetic recording medium having a magnetic layer formed on at least one surface of a nonmagnetic support, wherein the magnetic layer includes a ferrite ferromagnetic hexagonal powder having an average plate diameter of 5 to 50 nm or a fine ferromagnetic metal powder having an average major axis length of 20 to 100 nm together with a binder, and the nonmagnetic support is a composition of a polyester or copolyester having one or more of polytrimethylene 2,6-naphthalate, polytetramethylene 2,6-naphthalate, polypentamethylene 2,6-naphthalate and polyhexamethylene 2,6-naphthalate, in order to provides an excellent running stability, low error rates under various environment and an excellent electromagnetic transforming properties and reliability.Type: ApplicationFiled: March 26, 2007Publication date: September 27, 2007Applicant: FUJIFILM CorporationInventors: Katsuhiko Meguro, Masatoshi Takahashi
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Patent number: 7264893Abstract: The invention provides a magnetic recording medium comprising a support having provided thereon a nonmagnetic layer containing a nonmagnetic powder, and a magnetic layer containing a ferromagnetic powder formed on the nonmagnetic layer after coating and drying thereof, wherein the ferromagnetic layer is a hexagonal ferrite powder having an average tabular diameter of 15 to 40 nm or a ferromagnetic metal powder having an average major axis length of 25 to 100 nm, the thickness of the magnetic layer is from 0.01 to 0.3 ?m, the thickness of the nonmagnetic layer is from 0.5 to 5 ?m, and the specific surface area and the total pore volume of the magnetic recording medium itself measured by a nitrogen absorption measured method are from 0.1 to 50 m2/g and from 0.001 to 1 ml/g, respectively, thereby being to provide the magnetic recording medium for high density recording remarkably improved in electromagnetic characteristics, particularly in high density recording characteristics.Type: GrantFiled: April 30, 2004Date of Patent: September 4, 2007Assignee: FUJIFILM CorporationInventors: Takeshi Harasawa, Hiroaki Takano
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Patent number: 7208237Abstract: The present invention provides a magnetic recording medium comprising a thin film magnetic layer of thickness in a range from 0.03 to 0.30 ?m, and having excellent surface smoothness and superior electromagnetic conversion characteristics. The magnetic recording medium comprises a lower non-magnetic layer containing at least a non-magnetic powder and a binder resin on one surface of a non-magnetic support, an upper magnetic layer containing at least a ferromagnetic powder and a binder resin on the lower non-magnetic layer, and a back coat layer on the other surface of the non-magnetic support, wherein the thickness of the upper magnetic layer is within the range from 0.03 to 0.30 ?m, the AFM surface roughness Ra of the upper magnetic layer is 6 nm or less, and the number of concavities with a depth of 30 nm or greater in the surface of the upper magnetic layer is 5 per 1 cm2 of surface area or less.Type: GrantFiled: April 14, 2004Date of Patent: April 24, 2007Assignee: TDK CorporationInventors: Akihiko Seki, Takayoshi Kuwajima, Naoto Yajima, Hiroyuki Yamada, Kenichi Kitamura
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Patent number: 7118816Abstract: The present invention provides a magnetic recording medium comprising a support and a magnetic layer comprising a CuAu type or Cu3Au type magnetically hard ordered alloy phase, wherein a center line average roughness of a magnetic layer surface is 0.1 to 5 nm at a cut-off value of 0.25 mm, and a magnetic recording medium comprising a support and a magnetic layer containing, in a nonmagnetic metal oxide matrix, metal nanoparticles having a CuAu type or Cu3Au type magnetically hard ordered alloy phase.Type: GrantFiled: April 24, 2003Date of Patent: October 10, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Koukichi Waki, Yasushi Hattori
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Patent number: 7041397Abstract: A magnetic recording medium having on a nonmagnetic support at least one magnetic layer that contains a ferromagnetic metal powder and a binder and has surface roughness of 3 nm or below, with that the ferromagnetic metal powder has an average major-axis length of 30 to 100 nm and saturation magnetization ?s of 70 to 100 A·m2/kg and the magnetic layer further contains SiO2 grains having an average size of 5 to 30 nm, which shows excellent electromagnetic conversion characteristics, ensures reduction in MR head abrasion and has enhanced scratch resistance.Type: GrantFiled: December 30, 2003Date of Patent: May 9, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazuo Kato, Hiroaki Takano