With Post-treatment Of Coating Or Coating Material Patents (Class 427/130)
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Patent number: 5993956Abstract: The present invention provides for a magnetic recording media incorporating Mn-containing layers between a substrate and a magnetic layer to provide media having increased coercivity and lower noise. The Mn-containing layer can be incorporated in a rotating, translating or stationary recording media to operate in conjunction with magnetic transducing heads for recording and reading of magnetic data, as well as other applications. The magnetic recording medium of the invention preferably includes a Co or Co alloy film magnetic layer, and Mn-containing layer, preferably comprised of VMn, TiMn, MnZn, CrMnMo, CrMnW, CrMnV, and CrMnTi, and most preferably a CrMn alloy, disposed between the substrate and the magnetic layer to promote an epitaxial crystalline structure in the magnetic layer. The medium can further include seed layers, preferably polycrystalline MgO for longitudinal media, underlayers, and intermediate layers.Type: GrantFiled: April 22, 1997Date of Patent: November 30, 1999Assignee: Carnegie Mellon UniversityInventors: David N. Lambeth, Li-Lien Lee, David E. Laughlin
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Patent number: 5989673Abstract: Chromium-tantalum oxides (Cr-TaO.sub.x), including chromium-tantalum pentoxide (Cr-Ta.sub.2 O.sub.5), chromium-tantalum tetrioxide (Cr-Ta.sub.2 O.sub.4 or Cr-TaO.sub.2), sputtering targets containing them, and their manufacture are disclosed. The targets are characterized by high density, uniform TaO.sub.x distribution, low impedance and stable plasma during the sputtering. The Cr-Ta oxides are used as a thin film sublayer to improve the coercivity and other characteristics of magnetic recording media deposited on metallic or non-metallic substrates used in hard disks for data storage.Type: GrantFiled: June 30, 1997Date of Patent: November 23, 1999Assignees: Sony Corporation, Materials Research CorporationInventors: Wei Xiong, Hung-Lee Hoo
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Patent number: 5989674Abstract: A thin film disk and a disk drive using the thin film disk are described. The disk has a thin film magnetic layer composed of small acicular grains having an average aspect ratio greater than one which results in improved recording performance. The development of the acicularity is aided through the crystal structure having anisotropic inplane stress with a radial stress being less than a tangential stress. The preferred magnetic material is an alloy cobalt which includes a glass forming material such as boron, boron oxide, silicon, silicon oxide, carbon, phosphorus, etc. The typical hcp unit cells form acicular grains with a tendency for the C-axis to be orthogonal to a long axis of the acicular grains. Preferably the C-axis of the grains is oriented along the circumferential direction of the disk. Preferably the underlayer is sputtered deposited using negative bias.Type: GrantFiled: May 15, 1998Date of Patent: November 23, 1999Assignee: International Business Machines CorporationInventors: Ernesto Esteban Marinero, Timothy Martin Reith, Brian Rodrick York
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Patent number: 5989728Abstract: An alloy of tetragonal polycrystalline structure acts as a thin film magnetic medium. The medium can be for recording or sensing magnetic transitions representative of data and is of a thickness less than about 200 .ANG., and has a coercivity in excess of about 2000 Oe. The film is in the L1o phase which is suitable for longitudinal recording and can be constituted by an alloy selected from cobalt or iron together with platinum or palladium. The film is formed by sputtering from a target and thereafter annealing the thin film and at a temperature in excess of about 500.degree. C.Type: GrantFiled: June 12, 1996Date of Patent: November 23, 1999Assignee: International Business Machines CorporationInventors: Kevin Robert Coffey, James Kent Howard, Michael Andrew Parker
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Patent number: 5981039Abstract: A magnetic recording medium in accordance with the present invention is constituted by a first magnetic film having a magnetic anisotropy in a first direction parallel to the film surface and a second magnetic film that is formed on the first magnetic film and that is made of an amorphous alloy film of a rare-earth metal and a transition metal having a magnetic anisotropy in a second direction that is parallel to the film surface, and different from the first direction. In the above-mentioned magnetic recording medium, the first and second magnetic films have magnetic anisotropies having directions parallel to their surfaces and different from each other. When a magnetic latent image is formed on the magnetic recording medium of this type, it is possible to reduce the height of serration in the serrate magnetization transition structure appearing in the border of magnetization inversion in the magnetic latent image.Type: GrantFiled: August 27, 1997Date of Patent: November 9, 1999Assignee: Sharp Kabushiki KaishaInventors: Hitoshi Isono, Kazuo Van
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Patent number: 5980997Abstract: A method for manufacturing a magnetic disk comprises the step of depositing a metallic layer on a glass substrate and laser texturing the metallic layer. The magnetic disk is then completed by deposition of (a) an underlayer such as Cr or sputtered NiP, (b) a magnetic layer such as a Co or Fe alloy, and (c) a protective overcoat such as ZrO.sub.2, carbon or hydrogenated carbon. By providing the above-mentioned metallic layer, laser texturing can now be used in conjunction with glass substrates.Type: GrantFiled: June 3, 1996Date of Patent: November 9, 1999Assignee: Komag, IncorporatedInventors: Caroline A. Ross, Martin Philip Rosenblum
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Patent number: 5981093Abstract: A magneto-optical recording medium having a stack of magnetic layers which include at least one rare earth element and at least one transition metal element. At least one of the magnetic layers contain fluorine with an atomic concentration less than 1%. A process for producing a magneto-optical recording medium including magnetic layers. The process includes a step of controlling the Curie temperatures of the magnetic layers by controlling a fluorine atomic concentration of the magnetic layers.Type: GrantFiled: March 10, 1997Date of Patent: November 9, 1999Assignee: Commissariat a l'Energie AtomiqueInventors: Bernard Bechevet, Jacques Daval, Bruno Valon, Marie-Fran.cedilla.oise Armand
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Patent number: 5981053Abstract: This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180.degree. opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40.degree. C., is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable time limits.Type: GrantFiled: October 5, 1993Date of Patent: November 9, 1999Assignee: Sandia CorporationInventors: Richard Brian Naylor, Donald J. Sharp
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Patent number: 5981017Abstract: A magnetic disk which includes a thin film magnetic layer resistant to thermal erasures caused by a rise in localized temperature in the disk due to head disk interference includes a substrate having a thermal diffusivity of less than about 2.times.10.sup.-6 m.sup.2 /sec and a magnetic layer for storing information which is subject to erasure upon such use in localized temperature generated by the head disk interference. An underlayer below the magnetic layer is provided for orienting crystalline structure of the magnetic layer, and the heat sink layer directly above the substrate and directly below the underlayer has a single material such as chromium. The heat sink layer has sufficient thermal diffusivity and sufficient thickness for dissipating heat generated by the rise in localized temperature caused by head disk interference to prevent the erasure of stored information in the magnetic layer.Type: GrantFiled: December 19, 1997Date of Patent: November 9, 1999Assignee: Western Digital CorporationInventors: Shashi B. Agarwal, Debasis Baral, Jih-Ping Peng
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Patent number: 5976688Abstract: In a magneto-optical recording medium, a first dielectric layer 12, a recording layer 13, an auxiliary recording layer 14, a second dielectric layer 15 and a reflective layer 16 are sequentially laminated on a transparent substrate 11. Recording layer 14 is formed of a rare-earth transition-metal amorphous alloy having a film thickness of about several hundreds angstroms. Auxiliary recording layer 14 is also formed of a rare-earth transition-metal amorphous alloy. However, the Curie temperature T.sub.C2 of auxiliary recording layer 14 is 10.degree. K or more higher than the Curie temperature T.sub.C1 of recording layer 13, and the film thickness of auxiliary recording layer is ultra-thin, such as, 70 .ANG. or less. Further, the squareness ratio of auxiliary recording layer 14 at the Curie temperature T.sub.C1 of recording layer 13 is 0.7 or higher.Type: GrantFiled: August 15, 1997Date of Patent: November 2, 1999Assignee: Seiko Epson CorporationInventors: Takeo Kawase, Masaya Ishida, Satoshi Nebashi, Satoshi Shimokawato, Toshiaki Mikoshiba, Shoji Hoshina, Hiromu Miyazawa, Atsushi Takakuwa
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Patent number: 5972460Abstract: A highly reliable information recording medium capable of meeting a higher rotation speed of a drive device and a smaller thickness and a higher recording density of an information recording medium can be produced by using, as a substrate, chemically reinforced glass obtained from chemically reinforceable glass having an SiO.sub.2 --Al.sub.2 O.sub.3 --R.sub.2 O total content of more than 98% by weight and having a specific modulus of at least 30.times.10.sup.2.Type: GrantFiled: December 23, 1997Date of Patent: October 26, 1999Assignee: Hoya CorporationInventor: Kazuo Tachiwana
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Patent number: 5972420Abstract: A magnetoresistive sensor fabricated by creating first antiferromagnetic layers on the upper surfaces of a lower-gap layer, the antiferromagnetic layer having first and second exposed portions separated by a track width formed by the upper surface of the lower-gap layer. Then, a free magnetic layer, a nonmagnetic electrically conductive layer, a pinned magnetic layer and a second antiferromagnetic layer are stacked on the first antiferromagnetic layers and a portion on the track width one after another. Since the free magnetic layer is created after the first antiferromagnetic layer, the free magnetic layer and the first antiferromagnetic layer are adhered to each other with a high degree of reliability. When the direction of magnetization in the free magnetic layer is changed by an external magnetic field, the electrical resistance of the magnetoresistive sensor also changes. The change in electrical resistance is, in turn, used for detecting the external magnetic field.Type: GrantFiled: August 22, 1997Date of Patent: October 26, 1999Assignee: Alps Electric Co., LtdInventors: Masamichi Saito, Toshinori Watanabe, Kiyoshi Sato, Toshihiro Kuriyama
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Patent number: 5965230Abstract: A blank for magnetic hard disk and a method for producing the same are provided, characterized in that the attachment or adhesion of a blank of a disk shape to each other can be prevented when such blank is stacked together for disk annealing, thereby improving the productivity of magnetic hard disk, and that the damage of blank surface can be prevented during blanking. Firstly, an aluminium alloy plate is subjected to continuous surface washing process with an etching solution while winding off the aluminium alloy plate in a coil, whereby the oxide film on the surface of the aluminium alloy plate is removed to concurrently deposit insoluble smut on the surface. Then, the aluminium alloy plate after the washing process is pressed for blanking thereof into a blank of a disk shape.Type: GrantFiled: January 16, 1997Date of Patent: October 12, 1999Assignee: Kabushiki Kaisha Kobe Seiko ShoInventors: Tomoyuki Sugita, Yuichi Hayashi, Keiji Okada, Hideo Fujimoto
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Patent number: 5965194Abstract: In one aspect, the present invention concerns a process of making coated magnetic particles. According to this process, an aqueous sol of amorphous, hydrolyzed, aluminous, colloidal particles is mixed with an aqueous suspension comprising magnetic particles. The amorphous, hydrolyzed, aluminous, colloidal particles have a mean particle size in the range from about 0.5 to about 5 nanometers and an average degree of hydrolysis in the range from 1.5 to about 3. During mixing, the amorphous, hydrolyzed, aluminous, colloidal particles form a continuous, amorphous, aluminum hydrous oxide coating on the magnetic particles, wherein the coating has an average thickness in the range from about 0.5 to about 5 nanometers. The present invention also concerns coated magnetic particles. Coated magnetic particles according to the present invention comprise a magnetizable core and a continuous, amorphous, aluminum hydrous oxide coating formed on the magnetizable core.Type: GrantFiled: January 10, 1992Date of Patent: October 12, 1999Assignee: Imation Corp.Inventors: Jack G. Truong, Thomas E. Wood
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Patent number: 5965214Abstract: A method of fabricating a tag or marker carrying or intended to carry a magnetic code is described. The method comprises applying a particulate magnetic material to a surface region of the tag by a printing or transfer process. The particulate magnetic material is generally deposited in the form of discrete elements or indicia. A tag thus produced can be coded magnetically by magnetising the elements or indicia, e.g. with a permanent magnet. This provides a very versatile and relatively rapid means of generating coded tags or labels virtually without limit on the variety of codes which may be adopted.Type: GrantFiled: April 22, 1997Date of Patent: October 12, 1999Assignee: Flying Null LimitedInventors: Michael David Crossfield, Christopher John Coggill
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Patent number: 5961792Abstract: An improved magnetic-recording disk and a process for manufacturing magnetic-recording disks are disclosed. Precision cold-rolled titanium or titanium alloy is the substrate for a magnetic-recording disk. The surface of the substrate may be hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding. A hard coating may be applied to the substrate by evaporative reactive ion plating or reactive sputtering of aluminum nitride, silicon nitride, silicon carbide, or nitrides, carbides, or borides of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, or tungsten.Type: GrantFiled: April 18, 1997Date of Patent: October 5, 1999Assignee: Tulip Memory Systems, Inc.Inventors: Carl W. Nelson, Richard D. Weir, Richard S. Weir
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Patent number: 5958544Abstract: A magnetic recording medium comprises a non-magnetic substrate and a magnetic layer, which is constituted of a thin ferromagnetic metal film and is overlaid upon at least either one of the surfaces of the non-magnetic substrate. A prime-coating layer, which has alkyl chains linked by an ether linkage to each other in a polysiloxane, is formed between the non-magnetic substrate and the thin ferromagnetic metal film. The magnetic recording medium is capable of being produced easily and at a low cost. The prime-coating layer has smooth surface characteristics, is free from deterioration of surface characteristics and the occurrence of cracking even during the formation of a magnetic layer thereon with a sputtering process, and causes no blocking to occur.Type: GrantFiled: March 13, 1997Date of Patent: September 28, 1999Assignee: Fuji Photo Film Co., Ltd.Inventor: Kazuyuki Usuki
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Patent number: 5958542Abstract: A thin film magnetic disc in which dot-like scattered bumps, made of a material different from that of the protective layer, are formed on the protective layer, and a lubricant layer is formed on the surfaces of the protective layer and the scattered bumps. A protective layer excellent in strength and disk durability is obtained by using a material different from that of the bumps. The functions of the protective layer and scattered bumps are separated from each other and make full use of the different materials. Such a protective layer is effective to reduce spacing between a head and the disc.Type: GrantFiled: June 3, 1996Date of Patent: September 28, 1999Assignee: Hitachi, Ltd.Inventors: Mitsuyoshi Ootake, Yuichi Kokaku, Yoshinori Honda, Akira Kato, Hiroaki Hagimae, Heigo Ishihara, Kenji Furusawa
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Patent number: 5952041Abstract: A combined read/write thin film magnetic head comprises an upper-core layer formed on a lower-core layer through an insulating layer, a magnetic gap of a nonmagnetic material disposed between one end of the upper-core layer and the lower-core layer, the other end of the upper-core layer and the lower-core layer being magnetically connected to each other, a thin coil layer provided between the lower-core layer and the upper-core layer so as to surround the magnetically connected section, and an organic resin layer, provided beside both sides of the lower-core layer, having substantially the same thickness as the lower-core layer. The coil layer is formed on the core lower-core layer and the organic resin layer through an insulating layer.Type: GrantFiled: June 24, 1998Date of Patent: September 14, 1999Assignee: Alps Electric Co., Ltd.Inventors: Kiyoshi Sato, Naohiro Ishibashi
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Patent number: 5948553Abstract: A spin valve type multilayered magnetic structure has Fe-base soft magnetic crystalline layer having a mean grain size equal to or less than 30 nanometers and sandwiching a non-magnetic spacer layer, and the Fe-base soft magnetic crystalline layer is expressed as Fe-M-B where M is at least one transition metal selected from the group consisting of Sc, Ti, V, Cr, Y, Zr, Nb, Mo, La, Hf, Ta and W and B is selected from the group consisting of C, B and N; and the spin valve type multilayered magnetic structure achieves a large magnetoresistance ratio equal to or greater than 10.Type: GrantFiled: April 25, 1997Date of Patent: September 7, 1999Assignee: NEC CorporationInventor: Atsushi Kamijo
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Patent number: 5945156Abstract: A method of manufacturing a magnetic recording medium having excellent magnetostatic and electromagnetic conversion properties for high density recording is provided, wherein magnetic powder (P) is kneaded with a binding agent (B) mainly comprising low molecular weight vinyl chloride resin whose number-average molecular weight is 8000 to 20000 with a P/B ratio of 7 or more before preparing the magnetic coating material so as to be coated on a non-magnetic base material.Type: GrantFiled: August 7, 1997Date of Patent: August 31, 1999Assignee: Sony CorporationInventors: Yoshihiro Shimizu, Jun Hashimoto, Taro Ohmura
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Patent number: 5945219Abstract: A magnetic recording medium having at least a thin magnetic metal film and a carbon protective film formed on a non-magnetic substrate, wherein lubricating properties are afforded to a surface portion of the carbon protective film. Specifically, the carbon protective film having a lower layer exhibiting rust-proofing properties and/or an upper layer exhibiting lubricating properties is formed on the thin magnetic metal film. The magnetic recording medium has a good running performance, durability and preservability.Type: GrantFiled: March 26, 1996Date of Patent: August 31, 1999Assignee: Sony CorporationInventors: Yukari Yamada, Ryoichi Hiratsuka, Takahiro Kawana
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Patent number: 5939134Abstract: An improved process for making thin film magnetic heads using an insulation comprising a polymer, a crosslinking agent, and 4-sulfonate diazonaphthoquinone.Type: GrantFiled: July 31, 1997Date of Patent: August 17, 1999Assignee: International Business Machines CorporationInventors: Dennis Richard McKean, Alfred Floyd Renaldo
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Patent number: 5935644Abstract: The present invention uncouples the dependence between the zero throat height and the flare point of a write head by recessing the first insulation layer within the first pole piece layer. The first pole piece layer and the first insulation layer have planar surfaces which preferably lie in a common plane, the zero throat height being defined at the point where the planar surface of the first pole piece layer first meets the planar surface of the first insulation layer within the head. It is also at this point that the first and second pole piece layers separate from one another. Accordingly, the zero throat height can be accurately placed relative to the stripe height of a magneto-resistive (MR) sensor. Further, when a photoresist layer is spun onto the partially completed head for the construction of the pole tip of the second pole piece light directed into the photoresist layer for photo-imaging the pole tip does not reflect into the photoresist layer adjacent the pole tip.Type: GrantFiled: March 4, 1998Date of Patent: August 10, 1999Assignee: International Business Machines CorporationInventors: David Eugene Heim, Hugo Alberto Emilio Santini
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Patent number: 5932343Abstract: A magnetoresistive effect element has an NiO layer, an intermediate layer, a first ferromagnetic layer, a first MR enhancement layer, a non-magnetic layer, a second MR enhancement layer, a second ferromagnetic layer, and a protective layer, laminated in sequence onto an underlayer, the intermediate layer being made of a mixture of nickel oxide and a ferrous oxide materials.Type: GrantFiled: August 12, 1997Date of Patent: August 3, 1999Assignee: NEC CorporationInventors: Kazuhiko Hayashi, Masafumi Nakada
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Patent number: 5928715Abstract: A magnetoresistive read transducer includes a magnetoresistive (MR) layer having end regions spaced by a central active region. A pair of hard magnetic layers provide longitudinal magnetic bias to the MR layer, with each of the hard magnetic bias layers disposed in contact with one of the end regions of the MR layer. A pair of electrical lead members are disposed in contact with the end regions of the MR layer and with the hard magnetic bias layers. The hard magnetic bias layers and the electrical lead members are deposited, followed by selective removal of portions of the lead members to expose the edges of the hard bias material.Type: GrantFiled: July 28, 1997Date of Patent: July 27, 1999Assignee: Read-Rite CorporationInventors: Durga P. Ravipati, Steven Clark Rudy
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Patent number: 5925404Abstract: The quantity of impurities in a magnetic material is decreased to produce a magnetic material with good quality, and a decrease in the cost of the magnetic material is realized by desulfurization. A magnetic raw material for metallic thin film magnetic recording media which contains sulfur more than 20 ppm is desulfurized to obtain the magnetic material for metallic thin film magnetic recording media with the sulfur content adjusted to 20 ppm or below, and a metallic thin film magnetic recording medium having a magnetic layer vaporized thereon with the magnetic material is fabricated.Type: GrantFiled: October 6, 1997Date of Patent: July 20, 1999Assignee: Sony CorporationInventors: Kazunobu Chiba, Tustomu Takeda, Hiroyuki Yamada, Hideo Katagiri, Hiroshi Osumi
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Patent number: 5922177Abstract: A method to produce a magneto-optical recording medium which includes a readout layer having in-plane magnetization at room temperature and in which a transition occurs from in-plane magnetization to a perpendicular magnetization when temperature rises, and a recording layer for storing information thereon magneto-optically. In the readout layer made of GdFeCo by adding Nd thereto, an amount of Nd to be added changes in a direction perpendicular to its film surface, and an amount of Nd is larger on a light incidence side than on the other side. As a result, even when a laser with a short wavelength is used, high density recording can be achieved as undesirable recording and reproducing operations due to a change in a magnetic interaction is prevented and also deterioration in quality of a reproducing signal is prevented.Type: GrantFiled: July 9, 1998Date of Patent: July 13, 1999Assignee: Sharp Kabushiki KaishaInventors: Naoyasu Iketani, Yoshiteru Murakami, Akira Takahashi, Kenji Ohta
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Patent number: 5916641Abstract: The present invention provides for a number of interrelated methods for the production of random and ordered arrays of particles as well as films containing the same. In another aspect, the present invention relates to the random and ordered arrays of particles and films prepared therefrom. The ordered arrays are obtained by the use of ferrofluid compositions which may be curable, solidifiable or non-curing/non-solidifiable. Especially preferred arrays and films contain electrically conductive particles for use in electronic applications for effecting contact between leads or pads.Type: GrantFiled: August 1, 1996Date of Patent: June 29, 1999Assignees: Loctite (Ireland) Limited, Loctite CorporationInventors: Ciaran B. McArdle, Joseph Burke, Edward K. Welch, II
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Patent number: 5916355Abstract: A surface treatment is provided for magnetic media, in particular metal evaporated magnetic tape, that prevents or reduces corrosion in the media. A corrosion inhibitor and a coupling agent are added to a carrier, such as ethanol, and applied directly to the magnetic media. The corrosion inhibitor is advantageously a derivative of sarcosine, preferably N-methyl-N-(1-oxo-9-octadeconyl)glycine, and is added in an amount up to about 0.5 wt. %. The coupling agent is advantageously an organofunctional silane, preferably 3-glycidoxypropyltrimethoxysilane, and is added in an amount up to about 0.3 wt. %. This formula is particularly suitable for preventing corrosion in cobalt evaporated magnetic tape.Type: GrantFiled: August 11, 1998Date of Patent: June 29, 1999Assignees: Sony Corporation, Sony Electronics Inc.Inventors: Rymer Steven Willis, Scott Riley Brown
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Patent number: 5914151Abstract: A coating film, which is constituted of a polysilazane, is formed on a substrate. The polysilazane in the coating film is then oxidized by being brought into contact with active oxygen or ozone, or by being exposed to light. A protective film, which is constituted of silica, is thereby formed on the substrate. An inorganic protective film is also provided, which comprises an inorganic oxide film, that is obtained by subjecting a polysilazane coating film to oxidation treatment, and fine particles contained in the inorganic oxide film.Type: GrantFiled: May 29, 1996Date of Patent: June 22, 1999Assignee: Fuji Photo Film Co., Ltd.Inventor: Kazuyuki Usuki
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Patent number: 5914152Abstract: A magnetic recording medium comprised of (i) a non-magnetic substrate such as glass or carbon, (ii) a silicon layer preferably having a thickness of about 20-3,000 angstroms, formed on the substrate, (iii) a layer composed of at least one element of the platinum group of the periodic table or its alloy or carbon, formed on the silicon layer, wherein the platinum group element or alloy is at least partially silicified with silicon diffusing from the adjacent silicon layer, and the carbon is rendered at least partially amorphous with silicon diffusing from the adjacent silicon layer, (iv) an undercoat composed of chromium or its alloy, formed on the layer of a platinum group element or alloy or carbon, (v) a magnetic layer composed of a cobalt alloy, formed on the undercoat, (vi) a protective carbon overcoat formed on the magnetic layer, and (vii) an optional lubricating layer formed on the protective overcoat.Type: GrantFiled: November 7, 1997Date of Patent: June 22, 1999Assignee: Showa Denko Kabushiki KaishaInventors: Daizo Endo, Masato Fukushima, Shin-ichi Ogawa
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Patent number: 5910344Abstract: The present invention provides a magnetoresistive sensor having at least two ferromagnetic layers provided with a non-magnetic layer therebetween; a coercive force increasing layer consisting of an antiferromagnetic material and provided adjacent to one of the ferromagnetic layers, for increasing the coercive force thereof to pin magnetization reversal, the other ferromagnetic layer having free magnetization reversal; and an antiferromagnetic layer provided to adjacent to the other ferromagnetic layer having free magnetization reversal, for applying a longitudinal bias to the other ferromagnetic layer to induce magnetic anisotropy therein due to an unidirectional exchange bias magnetic field to stabilize a magnetic domain.Type: GrantFiled: October 20, 1998Date of Patent: June 8, 1999Assignee: Alps Electric Co., Ltd.Inventors: Naoya Hasegawa, Masamichi Saito, Akihiro Makino
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Patent number: 5910235Abstract: A stationary vacuum deposition machine is used in a method for controlling the height of bumps formed in annular regions of substrates; the substrates are transported to the machine in a first condition in which each substrate is subject to a chemicapillary effect when subjected to localized thermal heating and melting. The machine includes a series of stations including an entrance station for receiving substrates into the machine, first and second predetermined stations, and a transport for operating in a cycle with each cycle including a transport phase and a stationary phase such that the transport causes all the substrates that are in the machine to be moved during the transport phase, and be temporarily held stationary during the stationary phase, such that during each stationary phase a predetermined one of the stations is occupied by one of the substrates while each of a plurality of others of the stations is occupied by a respective one of a plurality of others of the substrates.Type: GrantFiled: September 12, 1997Date of Patent: June 8, 1999Assignee: Western Digital CorporationInventors: Stella Zofia Gornicki, Douglas J. Krajnovich
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Patent number: 5906885Abstract: A magnetic recording medium includes a flexible substrate, a coating layer formed on the flexible substrate, and a magnetic layer formed on the coating layer. The coating layer contains a binder and nonmagnetic particles and has a thickness in the range of 0.05 to 0.7 .mu.m as a result of a stretching treatment performed at least once after application of the coating layer on the flexible substrate. The magnetic layer contains magnetic powder, a binder and an abrasive and has a thickness in the range of 0.05 to 1.0 .mu.m. The nonmagnetic particles contained in the coating layer has an average particle size in the range of 0.01 to 0.08 .mu.m. The abrasive contained in the magnetic layer has an average particle size in the range of 0.05 to 0.8 .mu.m and satisfies conditions defined by the following equations (1) and (2):d.sub.mx .ltoreq.(d.sub.av .times.2.0)+0.5 equation (1)d.sub.mx .ltoreq.t.sub.c +t.sub.m +0.5 equation (2)wherein d.sub.mx represents a maximum particle size of the abrasive, d.sub.Type: GrantFiled: March 25, 1996Date of Patent: May 25, 1999Assignee: TDK CorporationInventors: Youichi Yoshimura, Shigeharu Watase
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Patent number: 5902172Abstract: In a method of polishing a Ni--P plated aluminum alloy memory disk substrate, the present invention provides a polishing method which can efficiently form a good polished surface having slight polishing flaws, restrain the generation of a defect other than the polishing flaws and has a high productivity. That is, in the method according to the present invention, an alumina abrasive grain is used as a polishing compound. The present invention solves the problem by dividing the polishing process into two steps. In the first step, a first polishing is performed in which the main work pressure is 80 g/cm.sup.2 or more and the amount of polishing is 1 .mu.m or more. A second polishing is then peformed in which the main work pressure is 80 g/cm.sup.2 or less, preferably 50 g/cm.sup.2 or less, and the amount of one-sided polishing is 2 .mu.m or less. A final finish polishing is performed for 10-60 seconds prior to the completion of the second polishing step in which the main work pressure is 30 g/cm.sup.Type: GrantFiled: August 22, 1997Date of Patent: May 11, 1999Assignee: Showa Aluminum CorporationInventor: Tomoya Utashiro
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Patent number: 5900126Abstract: An improved magnetic-recording disk and a process for manufacturing magnetic-recording disks are disclosed. A precision cold-rolled authentic stainless steel is the substrate for a magnetic-recording disk. The surface of the substrate may be hardened by plasma nitriding, plasma carburizing, or plasma carbonitriding. A hard coating may be applied to the substrate by evaporative reactive ion plating or reactive sputtering of aluminum nitride, silicon nitride, silicon carbide, or nitrides, carbides, or borides of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, or tungsten.Type: GrantFiled: June 3, 1996Date of Patent: May 4, 1999Assignee: Tulip Memory Systems, Inc.Inventors: Carl W. Nelson, Richard D. Weir
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Patent number: 5897969Abstract: A magnetic domain controlling film for controlling the magnetic domain of a magnetoresistive film is formed by the patterning technique on a lower insulating film formed on a lower shield film. The magnetoresistive film is formed on the magnetic domain controlling film for converting a magnetic signal from a magnetic recording medium into an electrical signal using the magnetoresistive effect. A resist pattern is formed by the lift-off method on the magnetoresistive film in such a fashion as to leave a region of the magnetoresistive film corresponding to the tracks of the magnetic recording medium. A magnetoresistive element is formed by ion milling leaving only the portion of the magnetoresistive film corresponding to the tracks.Type: GrantFiled: November 20, 1997Date of Patent: April 27, 1999Assignee: Hitachi, Ltd.Inventors: Akira Taniyama, Makoto Morijiri, Haruko Tanaka, Isamu Yuito, Eiji Ashida, Hiroaki Koyanagi, Hideo Tanabe, Tetsuo Kobayashi
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Patent number: 5879783Abstract: A magnetic recording medium exhibiting low medium noise is formed by depositing a seed layer on a glass or a glass-ceramic substrate and oxidizing the deposited seed layer, under controlled conditions to induce controlled surface microroughness. The subsequently sputter deposited underlayer exhibits a fine average grain size, such as less than about 20 nm. The magnetic alloy sputter deposited and epitaxially grown on the underlayer exhibits a fine average grain size, such as less than about 15 nm, and magnetic clusters reduced in size.Type: GrantFiled: January 2, 1997Date of Patent: March 9, 1999Assignee: Seagate Technology, Inc.Inventors: Jyh-Kau Chang, Qixu Chen, Ga-Lane Chen
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Patent number: 5876848Abstract: A method of forming a magnetic structure having layers with different magnetization orientations provided by a common magnetic bias layer includes the steps of depositing an antiferromagnetic layer between first and second ferromagnetic layers. During the deposition of the first and second ferromagnetic layers, magnetization fields of different orientations are employed separately to induce different directions of magnetization in the first and second layers. The different directions of magnetization in the first and second layers are sustained, through the process of exchange coupling, by the interposed antiferromagnetic layer which serves as the bias layer. A magnetic structure thus fabricated, can be used as a read transducer capable of generating differential signals with common mode noise rejection, and can be used as a magnetic pole for a magnetic head with reduced Barkhausen noise.Type: GrantFiled: February 3, 1997Date of Patent: March 2, 1999Assignee: Read-Rite CorporationInventors: Minshen Tan, Hua-Ching Tong, Francis H. Liu, Swie-In Tan
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Patent number: 5871625Abstract: Magnetic composites exhibit distinct flux properties due to gradient interfaces. The composites can be used to improve fuel cells and batteries and effect transport and separation of different chemical species. Devices utilizing the composites include an electrode and improved fuel cells, batteries. Some composites, disposed on the surface of electrodes, prevent passivation of those electrodes and enable direct reformation of liquid fuels. Methods involving these composites provide distinct ways for these composites to be utilized.Type: GrantFiled: June 6, 1996Date of Patent: February 16, 1999Assignee: University of Iowa Research FoundationInventors: Johna Leddy, Lois Anne Zook, Sudath Amarasinghe
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Patent number: 5869148Abstract: A process for the in-line, high speed manufacturing of magnetic products is disclosed. The process comprises the steps of printing onto a substrate, drying the ink print, making the appropriate cuts or scores on the substrate, applying a slurry of magnetizable material onto the substrate to create the magnet, drying the applied material, magnetizing the magnetic material and cutting and forming the substrate to the desired dimensions. Each of these steps may be performed in a single, in-line manufacturing operation running at high speeds.Type: GrantFiled: February 9, 1993Date of Patent: February 9, 1999Assignee: Webcraft Technologies Inc.Inventors: Stanford B. Silverschotz, Louis Rua, Jr., Christopher Tararuj, Armin A. Apel, George P. Hipko
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Patent number: 5866227Abstract: A magnetic recording medium comprising a glass or glass-ceramic substrate is formed by sequentially depositing thereon a partially oxidized NiP seed layer, an underlayer and a magnetic layer. The partially oxidized NiP seed layer is formed by reactive sputtering in a gas mixture of argon and oxygen. The resulting magnetic recording medium exhibits low medium noise and high coercivity rendering it suitable for high density magnetic recording.Type: GrantFiled: August 20, 1996Date of Patent: February 2, 1999Assignee: Seagate Technology, Inc.Inventors: Qixu Chen, Ga-Lane Chen
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Patent number: 5866212Abstract: A magnetoresistive (MR) sensor for MR heads comprising a magnetoresistive ferromagnetic layer (MR layer) and an antiferromagnetic layer in direct contact with the surface of the MR layer. The MR layer has a face-centered-cubic (fcc) structure. The crystalline structure of the antiferromagnetic layer is the fcc structure in the vicinity of the interface of the MR layer and the antiferromagnetic layer, and continuously changes to a face-centered-tetragonal (fct) structure toward the surface opposite to the interface. The interface of the MR layer and the antiferromagnetic layer is continuous with respect to the crystalline structure due to the epitaxial growth of the antiferromagnetic layer on the surface of the MR layer.Type: GrantFiled: February 20, 1998Date of Patent: February 2, 1999Assignee: Hitachi Metals, Ltd.Inventors: Hisao Kurosawa, Chiharu Mitsumata, Toshio Kobayashi, Shin Noguchi
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Patent number: 5858474Abstract: A magnetic medium has permanently defined boundaries between tracks and a consistent surface smoothness. The crystallographic structure of the magnetic medium is modified at the track boundaries, so the grains of the magnetic thin film permanently take on a relatively non-magnetic structure as compared to the grains of the magnetic thin film within the tracks. Servo patterns on the magnetic medium may be permanently defined at the same time the track boundaries are permanently defined. Laser ablation, laser heating to an amorphous structure, photolithography, perpendicular deposition, ion milling, reverse sputtering, and ion implantation can be used individually or in combination, with either the magnetic layer or the underlayer, to create the relatively non-magnetic areas.Type: GrantFiled: November 27, 1996Date of Patent: January 12, 1999Assignee: Seagate Technology, Inc.Inventors: Dallas W. Meyer, Zine-Eddine Boutaghou, Bo Wei
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Patent number: 5856008Abstract: An article that uses a magnetoresistive material comprising one or more CrO.sub.2 grains having an insulating material, advantageously Cr.sub.2 O.sub.3, along at least a portion of the grain boundary or boundaries, the magnetoresistive article advantageously exhibiting a magnetoresistance ratio greater than 12% at 5K and 20 kOe.Type: GrantFiled: June 5, 1997Date of Patent: January 5, 1999Assignee: Lucent Technologies Inc.Inventors: Sang-Wook Cheong, Harold Yoonsung Hwang
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Patent number: 5851582Abstract: The disclosure describes a magnetic recording medium comprising:a substrate;an NiO primary layer which is formed on the substrate and in which the plane (200) is substantially oriented in parallel with the surface of the substrate; anda Co-containing maghemite thin film which is formed on the NiO primary layer and in which the plane (400) is substantially oriented in parallel with the surface of the substrate, the molar ratio of Co to Fe is not less than 0.01 to less than 0.10, and the spacing of the plane (400) is not more than 2.082 .ANG..Type: GrantFiled: October 7, 1996Date of Patent: December 22, 1998Assignee: Toda Kogyo CorporationInventors: Kousaku Tamari, Takanori Doi
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Patent number: 5851363Abstract: Pt/Co multilayer materials systems having a thin metal interlayer possess superior room temperature coercivity, a square polar Kerr hysteresis loop, sufficient polar Kerr rotation, and are suitable for magneto-optical recording.These material systems allow the reading and writing of information from the substrate side of the multilayer film.Type: GrantFiled: August 26, 1994Date of Patent: December 22, 1998Assignee: Johnson Matthey Public Limited CompanyInventors: Joseph Miller, Derek P A Pearson, Philip G Pitcher
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Patent number: 5849386Abstract: An improvement in a magnetic recording medium having an underlayer and a magnetic recording layer is described. The improvement, effective to reduce media anisotropy, includes deposition of a prelayer on the substrate, prior to deposition of the underlayer. The prelayer is deposited to a thickness of between 10-60 .ANG. and is composed of an CoCr-based alloy having a defined saturation magnetization.Type: GrantFiled: August 7, 1997Date of Patent: December 15, 1998Assignee: HMT Technology CorporationInventors: Brij Bihari Lal, Sudhir S. Malhotra, Michael A. Russak
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Patent number: 5843521Abstract: A method for forming a magnetic transducer, and a magnetic transducer formed through the method. There is first provided a substrate. There is then formed over the substrate a first magnetic pole layer. There is then formed upon the first magnetic pole layer a gap filling dielectric layer. There is then formed upon the gap filling dielectric layer a seed layer. There is then formed upon the seed layer a photoresist frame employed in a photoresist frame plating method for forming a plated second magnetic pole layer upon the seed layer, where a base of a sidewall of the photoresist frame has a taper which provides a notch within an edge of the plated second magnetic pole layer at its interface with the seed layer.Type: GrantFiled: July 21, 1997Date of Patent: December 1, 1998Assignee: Headway Technologies, Inc.Inventors: Kochan Ju, Mao-Min Chen, Yimin Guo