Magnetic Feature Patents (Class 428/900)
  • Patent number: 6541104
    Abstract: A magnetic recording medium has a construction in which on a non-magnetic support member are successively stacked a seed layer made of a non-magnetic material that is mainly composed of Cr, a keeper layer made of an NiFe-type soft magnetic material, an intermediate layer made of a non-magnetic material that is mainly composed of Cr and a recording layer made of a magnetic material that is mainly composed of Co.
    Type: Grant
    Filed: March 8, 2001
    Date of Patent: April 1, 2003
    Assignee: Fujitsu Limited
    Inventors: Hideyuki Akimoto, Chiaki Okuyama, Iwao Okamoto
  • Patent number: 6541431
    Abstract: The present invention provides a lubricant for magnetic recording medium which comprises, as an effective component, a phosphazene compound of formula [N═P[O(C6H4)—(A)z—R]a[OCH2—(B)xH]b]y  (1) wherein A is —C6H4— or —OC6H4—, B is fluorine-containing alkylene group, R is hydrogen atom, fluorine atom, C1-4 alkyl, C1-4 alkoxy or C1-4 haloalkyl, a and b are a real number of 0 to 2, satisfying a+b=2, x is 1, 2, 3 or 4, y is 3 or 4, and z is 0 or 1.
    Type: Grant
    Filed: January 22, 2001
    Date of Patent: April 1, 2003
    Assignee: Matsumura Oil Research Corp.
    Inventors: Tamio Akada, Yoshinobu Fujii, Nagayoshi Kobayashi, Rie Fujimoto
  • Publication number: 20030059603
    Abstract: Pyrogenic, oxidic particles contain superparamagnetic metal oxide domains with a diameter of 3 to 20 nm in a non-magnetic metal or non-metal oxide matrix. The particles display a chloride content of 50 to 1000 ppm. The particles are produced by pyrogenic processes by mixing the precursor of the superparamagnetic domains and the precursor of the non-magnetic metal or non-metal oxide matrix in a flame with air and/or oxygen and fuel gas and reacting this mixture in a flame. The particles can be used as ferro fluids, for example.
    Type: Application
    Filed: August 16, 2002
    Publication date: March 27, 2003
    Applicant: DEGUSSA AG
    Inventors: Heiko Gottfried, Christian Janzen, Markus Pridoehl, Paul Roth, Berthold Trageser, Guido Zimmermann
  • Patent number: 6537643
    Abstract: In an adhering closure element with a carrier strip (10) with meshing parts (12) arranged on it, and with a cover strip (20) covering the carrier strip (10) on the side turned away from the meshing parts (12), which is wider than the carrier strip (10), the two free side edge areas (21) of the cover strip (20) are folded over themselves, in the direction of the carrier strip (10) along a fold line (29), which runs in the longitudinal direction, so that the end edges (31) of the free side edge areas (21) of the cover strip (20) face the longitudinal edges (33) of the carrier strip (10).
    Type: Grant
    Filed: October 13, 2000
    Date of Patent: March 25, 2003
    Assignee: Gottlieb Binder GmbH & Co.
    Inventor: Konstantinos Poulakis
  • Patent number: 6537648
    Abstract: A substrate for an information recording medium has a microwaviness average height Ra′ not greater than 0.05 microinch as measured by a contactless laser interference technique for measurement points within a measurement region of 50 &mgr;m□-4 mm□ on a surface of the substrate.
    Type: Grant
    Filed: March 31, 2000
    Date of Patent: March 25, 2003
    Assignee: Hoya Corporation
    Inventors: Kouji Takahashi, Takemi Miyamoto, Hiroshi Tomiyasu, Genshichi Hata, Tomotaka Yokoyama
  • Patent number: 6537638
    Abstract: A perpendicular magnetic recording disk has an underlayer structure that causes the magnetic layer to have perpendicular magnetic anisotropy and high signal-to-noise ratio (SNR). The underlayer structure comprises a B2 type body-centered-cubic (BCC) material, such as the binary alloys NiAl, RuAl and RuTi, as an underlayer, and a Ti or TiCr alloy sublayer formed directly on the underlayer. The magnetic layer, such as a CoCrPt alloy, is deposited directly on the sublayer. The magnetic layer has perpendicular magnetic anisotropy due to the sublayer yet excellent SNR because of the smaller grain size of the sublayer material formed directly on the B2 type underlayer.
    Type: Grant
    Filed: December 13, 2000
    Date of Patent: March 25, 2003
    Assignee: International Business Machines Corporation
    Inventors: Hoa Do, Yoshihiro Ikeda, Yoshiaki Sonobe, Kentaro Takano
  • Patent number: 6537684
    Abstract: A magnetic recording medium for data storage uses a magnetic recording layer having at least two ferromagnetic films exchange coupled together antiferromagnetically across a nonferromagnetic spacer film. In this antiferromagnetically-coupled (AFC) recording layer the magnetic moments of the two ferromagnetic films are oriented antiparallel, and thus the net remanent magnetization-thickness product (Mrt) of the AFC recording layer is the difference in the Mrt values of the two ferromagnetic films. This reduction in Mrt is accomplished without a reduction in thermal stability of the recording medium. The lower ferromagnetic film in the AFC recording layer is a boron-free ferromagnetic CoCr alloy that does not require a nucleation layer between it and the Cr alloy underlayer.
    Type: Grant
    Filed: August 4, 2000
    Date of Patent: March 25, 2003
    Assignee: International Business Machines Corporation
    Inventors: Mary Frances Doerner, Eric Edward Fullerton, David Thomas Margulies
  • Patent number: 6534206
    Abstract: A magneto-optical storage apparatus including an ultra-high density information recording media having an inorganic compound layer 12 on a substrate 11, and in the inorganic compound layer 12, an oxide of at least one kind selected from silicon oxide, aluminum oxide, titanium oxide, tantalum oxide, and zinc oxide exists in an amorphous state at a grain boundary of crystal grain of an oxide of at least one kind selected from cobalt oxide, iron oxide, and nickel oxide. The media has a magnetic layer 13 made of an artificial lattice multilayer obtained by alternately laminating a Co layer or an alloy layer consisting of Co as a main phase and a metal element layer of at least one kind selected from Pt and Pd onto the layer 12. Thus, a distribution of magnetic properties serving as a pinning site of the movement of a magnetic wall in case of recording information to the magnetic layer 13 is formed in the magnetic layer 13.
    Type: Grant
    Filed: June 27, 2000
    Date of Patent: March 18, 2003
    Assignees: Hitachi, Ltd., Hitachi Maxell, Ltd.
    Inventors: Fumiyoshi Kirino, Nobuyuki Inaba, Hiroki Yamamoto, Takashi Naitou, Ken Takahashi, Eiji Koyama, Motoyasu Terao, Sumio Hosaka, Hiroki Kuramoto
  • Patent number: 6534203
    Abstract: A magnetic recording medium includes an anti-ferromagnetic layer 2 layered on at least one of the opposite major surfaces in a direction along the thickness of a ferromagnetic recording layer 3. It is possible for magnetization in the vicinity of a surface of an anti-ferromagnetic layer 2 facing a ferromagnetic recording layer 3 to be rotated simultaneously with rotation of magnetization of the ferromagnetic recording layer 3. It is also possible for the intensity of exchange coupling between the two layers to be larger than the total magnetic anisotropy of the anti-ferromagnetic layer 2. It is similarly possible for the intensity of the exchange coupling between the two layers to be smaller than the total magnetic anisotropy of the anti-ferromagnetic layer 2 and larger than the magnetic domain energy of the anti-ferromagnetic layer 2.
    Type: Grant
    Filed: March 25, 1999
    Date of Patent: March 18, 2003
    Assignee: Sony Corporation
    Inventors: Yoh Iwasaki, Minoru Ikarashi, Masafumi Takiguchi
  • Patent number: 6534205
    Abstract: There is provided a magnetic storage medium capable of recording information at high recording density and also to regenerating the information with a high quality of signal (high S/Nm), and in addition contributing to the elongation of a life span of the recorded information. The magnetic storage medium comprises a non-magnetic substrate and a magnetic recording layer provided on the substrate. The magnetic recording layer has a ferromagnetic grain consisting of a ferromagnetic material and an antiferromagnetic matrix consisting of an antiferromagnetic material.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: March 18, 2003
    Assignee: Fujitsu Limited
    Inventors: Hisateru Sato, Isatake Kaitsu, Iwao Okamoto
  • Patent number: 6534204
    Abstract: There is provided a magnetic storage medium capable of recording information at high recording density and also regenerating the information with a high quality of signal (high S/Nm), and in addition contributing to the elongation of a life span of the recorded information. The magnetic storage medium comprises a non-magnetic substrate, a plurality of magnetic recording layers of ferromagnetism formed on the non-magnetic substrate, and a dividing layer of antiferromagnetism for dividing said plurality of magnetic recording layers from one another through intervening between the magnetic recording layer-to-layer.
    Type: Grant
    Filed: September 24, 1999
    Date of Patent: March 18, 2003
    Assignee: Fujitsu Limited
    Inventors: Hideyuki Akimoto, Yuki Yoshida, Kenji Sato, Iwao Okamoto
  • Patent number: 6534168
    Abstract: Provided is a magnetic recording medium exhibiting a high C/N (low noise) ratio in high-density magnetic recording. A magnetic recording medium which comprises a nonmagnetic lower layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder provided in this order on a flexible nonmagnetic support. The nonmagnetic lower layer comprises flat acicular &agr;-iron oxide powder with a major axis length ranging from 0.05 to 0.5 &mgr;m and a ratio of the major width to the minor width (major width/minor width) of the minor axis cross-section when sectioned at an angle perpendicular to the major axis is equal to or higher than 1. The granular nonmagnetic particles have a mean particle diameter equal to or less than 0.04 &mgr;m.
    Type: Grant
    Filed: August 23, 2001
    Date of Patent: March 18, 2003
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Koji Naoe, Kiyomi Ejiri
  • Patent number: 6534164
    Abstract: Magnetic recording medium includes at least two layers having different magnetic anisotropy constants formed on a substrate and the perpendicular magnetic anisotropy of the second magnetic film of those magnetic films, far from the substrate surface, made equal to or larger than that of the first magnetic film near to the substrate surface, thus improving the magnetic isolation.
    Type: Grant
    Filed: September 7, 2001
    Date of Patent: March 18, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
  • Patent number: 6531202
    Abstract: The present invention provides perpendicular recording media having a soft magnetic underlayer and magnetic regions which generate an external magnetic field in the soft magnetic underlayer. The soft magnetic underlayer is brought into a substantially single-domain state by the magnetic field, thereby reducing or eliminating unwanted noise in the soft underlayer. In a preferred embodiment, the recording medium includes a ring-shaped soft magnetic underlayer positioned between concentric ring-shaped magnetic regions.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: March 11, 2003
    Assignee: Seagate Technology LLC
    Inventors: Dmitri Litvinov, Sakhrat Khizroev, Mark Howard Kryder
  • Publication number: 20030039863
    Abstract: A magnetic recording media is formed with high in-plane coercivity employing dual magnetic layers. The first magnetic layer is sputter deposited in a chamber employing a shield such that the minimum incident angle of impinging atoms is relatively large, e.g., greater than about 26°. Embodiments of the present invention comprise depositing a NiAI seedlayer, a Cr or Cr alloy underlayer and a first CoCrTa magnetic layer at a thickness less than about 50Å for inducing the preferred (10.0) crystallographic orientation in the subsequently deposited second magnetic layer, e.g., CoCrPtTa or CoCrPtTaNb having a high Cr content of about 16 to about 21 at.%.
    Type: Application
    Filed: September 24, 2002
    Publication date: February 27, 2003
    Applicant: Seagate Technology LLC.
    Inventors: Qixu (David) Chen, Lin Huang, Charles Leu, Rajiv Yadav Ranjan
  • Patent number: 6524730
    Abstract: A multilayer superlattice having a structure with many interfaces of magnetic/non-magnetic layers could increase the coercivity of a magnetic recording medium by increasing the interfacial anisotropy. A soft magnetic layer comprising interstitial nitrogen between the substrate and the multilayer superlattice reduces the surface roughness between the substrate magnetic layer. This in turn reduces the fly height and boosts the coercivity of the magnetic recording medium.
    Type: Grant
    Filed: August 14, 2000
    Date of Patent: February 25, 2003
    Assignee: Seagate Technology, LLC
    Inventor: Ga-Lane Chen
  • Patent number: 6524724
    Abstract: High areal density magnetic recording media exhibiting low noise are formed with a Ni—P—X plating layer, in which X is an additive meeting the following requirement: (1) The additive has a higher oxidation potential than that of Ni so that grains of an additive-rich-oxide will form first during oxidation under a controlled atmosphere and grains of a Ni-rich-oxide, if any, will form subsequently and separately from the grains of the additive-rich oxide. (2) The additive has a tendency to segregate to the top surface. (3) The additive is not a catalyst poison for Ni—P plating in the composition range.
    Type: Grant
    Filed: February 9, 2001
    Date of Patent: February 25, 2003
    Assignee: Seagate Technology LLC
    Inventors: Yuanda Randy Cheng, Connie Chunling Liu, Chung Shih, Linda Lijun Zhong, Jeff Duane St. John, Jeffery Lee Petrehn
  • Patent number: 6521341
    Abstract: The invention concerns magnetic and heat-sensitive particles having a predetermined size between 0.05 and 10 &mgr;m, each particle comprising: an inner composite core consisting of a solid organic or inorganic particle, containing within it a magnetic filler; an outer coati based on a polymer capable of interacting with at least a biological molecule, the outer polymer is heat-sensitive and has a predetermined low critical solubility temperature (LCST) ranging between 10 and 100° C. and preferably between 20 and 60° C. The invention also concerns methods for obtaining said particles and their uses. The particles are characterized in that there is an intermediate layer between the inner core and the outer layer isolating said inner core magnetic filler with respect to said functionalized outer layer. Said invention is particularly useful for separating proteins and/or nucleic acids.
    Type: Grant
    Filed: September 21, 2000
    Date of Patent: February 18, 2003
    Assignee: Bio Merieux
    Inventors: Abdelhamid Elaissari, Christian Pichot, Bernard Mandrand
  • Patent number: 6517942
    Abstract: A magnetic recording medium includes a magnetic layer, main components of which are magnetic powder and a binder, and a non-magnetic substrate on which the magnetic layer is formed. The binder is a polyurethane resin including a propanediol derivative expressed by the following general formula as an ingredient. The polyurethane resin has a urethane group concentration of 4,000 or more equivalents per 1 t of the resin, and a glass transition temperature of 100° C. or more, preferably, where either or both of R1 and R2 in the general formula is a saturated hydrocarbon group having a carbon number of 2 to 8 and the remnant is a saturated hydrocarbon.
    Type: Grant
    Filed: October 27, 2000
    Date of Patent: February 11, 2003
    Assignee: Sony Corporation
    Inventors: Toshitsugu Ono, Tomohiro Sato, Yuji Aoyama
  • Publication number: 20030019096
    Abstract: In accordance with the invention, a magnetic device is made by providing magnetic sheet layers with reactive joining materials that will react to join the layers into a unitary body. The joining materials are reacted, and the device is formed. In a preferred embodiment, the magnetic material is a soft magnetic material such as FeCo alloy, and the reactive joining materials are aluminum and FeCoOx which react to form nonconducting alumina layers between magnetic regions.
    Type: Application
    Filed: June 24, 2002
    Publication date: January 30, 2003
    Inventor: Timothy P. Weihs
  • Patent number: 6511761
    Abstract: In a magnetic storage apparatus including a recording medium having a magnetic layer, a seed layer and an underlayer formed on a substrate, a driver for driving the recording medium, a magnetic head having an inductive recording head and a magnetoresistive reproducing head, and a signal processing system for processing input signals to the magnetic head and output signals from the magnetic head, the seed layer comprises an amorphous alloy or a microcrystal alloy containing Ni, Ta and Zr, the underlayer comprises an alloy containing Cr as a main component and Ti, and the magnetic layer has a first magnetic layer in contact with the underlayer and a second magnetic layer on the first magnetic layer. The first magnetic layer comprises a Co—Cr—Pt alloy and the second magnetic layer comprises Co—Cr—Pt—B alloy, both of a substantially hexagonal close-packed structure.
    Type: Grant
    Filed: September 18, 2000
    Date of Patent: January 28, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Kiwamu Tanahashi, Tetsuya Kanbe, Satoshi Matsunuma, Akira Ishikawa
  • Patent number: 6509111
    Abstract: A magnetic recording media formed of magnetic alloy layer of Co as the main component on a substrate through an under-layer, a protective layer and a lubricant layer, stacked in this order, said under-layer comprises plural under-layers including a first under layer of a substantially amorphous and a second under layer of crystalline stacked in this order; and a &Dgr;BH[0.01, 50] defined by |BH[0.01%]−BH[50%]|, as the difference between a height BH[0.01%] where a Bearing ratio is 0.01% and a height BH[50%] where a Bearing ratio is 50%, is not less than 3 nm and not more than 6 nm, where a Bearing Curve is given by a surface roughness curve of magnetic recording media.
    Type: Grant
    Filed: June 30, 2000
    Date of Patent: January 21, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Mitsuhiro Shoda, Naoto Endo, Noriyoshi Goda, Yuzuru Hosoe, Akira Kato
  • Patent number: 6509083
    Abstract: Reproducible texturing of magnetic recording media is enhanced by sputtering a buffer layer, such as Ni-P, on a nonmagnetic substrate, prior to sputtering a textured bump layer. A magnetic recording medium comprising a sputter textured metal layer and high coercivity is achieved by employing an underlayer, such as NiAl or FeAl, preferably a composite underlayer containing a chromium or chromium-alloy layer and a NiAl layer, on the sputter textured layer. Advantageously, the buffer layer, underlayer, textured bump layer, magnetic layer and carbon overcoat can be sputter deposited in a single apparatus.
    Type: Grant
    Filed: January 25, 2001
    Date of Patent: January 21, 2003
    Assignee: Seagate Technology LLC
    Inventors: Xing Song, Ga-Lane Chen, Charles Leu, Qixu Chen
  • Patent number: 6506470
    Abstract: The present invention provides a magnetic recording medium having high electromagnetic transfer characteristics in a high-density recording medium. The invention provides a magnetic recording medium, which comprises a nonmagnetic primer layer placed on a nonmagnetic support member and at least one layer of magnetic layers with ferromagnetic powder dispersed in a binder, said magnetic layer being placed on said primer layer, whereby diamond particles with average particle size of 0.05 to 1 &mgr;m are added to the magnetic layer, and at least one type of compound selected from the following genera formulae (1) and (2) is contained: where R1 represents an alkyl group having 1 to 2 carbon atoms; and R2, R3 and R4 each represents a hydrocarbon group having 4 to 21 carbon atoms.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: January 14, 2003
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Takeshi Harasawa, Hiroshi Hashimoto, Hitoshi Noguchi, Shinji Saito
  • Patent number: 6506508
    Abstract: In a magnetic recording medium including an underlayer made of an anti-ferromagnetic material and a magnetic recording layer made of a material containing cobalt as the principal component that are serially disposed on a non-magnetic substrate, an intermediate layer made of a ferromagnetic material is sandwiched between the underlayer and the magnetic recording layer. A magnetic recording medium capable of providing an improved S/N ratio and high-density recording is provided. A production method for such a magnetic recording medium and a magnetic storage apparatus using the same are also provided.
    Type: Grant
    Filed: September 21, 2000
    Date of Patent: January 14, 2003
    Assignee: Fujitsu Limited
    Inventors: Yuki Yoshida, Iwao Okamoto
  • Patent number: 6503600
    Abstract: In a magnetic recording medium, surface roughness of a glass substrate and the variation of the surface roughness are suppressed to the predetermined range. Namely, the surface roughness (Rmax, Ra, Rq) and the relation (Rmax/Ra) between Rmax and Ra are restricted to the predetermined range. In this event, Ra is representative of a center-line mean roughness, Rmax is defined as a maximum height representative of a difference between a highest point and a lowest point and Rq is representative of a root mean square roughness. Thereby, crystal grains of an underlying layer and a magnetic layer formed thereon are equalized. Specifically, the surface roughness is specified by Rmax≦15 nm, Ra≦1 nm and Rq≦1.5 nm. Further, the ratio between the surface roughness Rmax and the surface roughness Ra is specified by Rmax/Ra≦30.
    Type: Grant
    Filed: June 15, 2001
    Date of Patent: January 7, 2003
    Inventors: Tsuyoshi Watanabe, Koji Takahashi, Masao Takano
  • Patent number: 6503762
    Abstract: A novel magnetic carrier is provided which comprises particulate silica containing a magnetic material, having polyacrylamide on the surface thereof in an amount ranging from 0.3 to 5 mmol/g in terms of monomeric acrylamide. A process for producing the magnetic carrier is also provided in which the surface of particulate silica containing a magnetic material is treated with a coupling agent, and the treated particulate silica is reacted with acrylamide and/or polyacrylamide. The magnetic carrier is useful for extraction of nucleic acid. The magnetic carrier can be produced readily by controlling the shape, the particle diameter, and the pore diameter, and is excellent in strength and adsorption efficiency. The extraction of a nucleic acid can be automated by use of the magnetic carrier.
    Type: Grant
    Filed: November 1, 2000
    Date of Patent: January 7, 2003
    Assignee: Tosoh Corporation
    Inventors: Syoichi Yamauchi, Kiyoshi Kasai
  • Patent number: 6501271
    Abstract: A robust Giant Magneto Resistive effect type multilayer sensor comprising a free and a pinned ferromagnetic layer, which can withstand high temperatures and strong magnetic fields as required in automotive applications. The GMR multi-layer has an asymmetric magneto-resistive curve and enables sensors with complementary output signals so that a Wheatstone bridge is possible. The improvement is obtained by a combination of measures including the use of a combination of an Artificial Anti Ferromagnet as the pinned layer and an IrMn exchange-biasing layer, the latter preferably arranged at the bottom of the layer stack on top of a buffer layer.
    Type: Grant
    Filed: May 6, 1999
    Date of Patent: December 31, 2002
    Assignee: Koninkiljke Philips Electronics N.V.
    Inventors: Kars-Michiel H. Lenssen, Antonius E. T. Kuiper, Freddy Roozeboom
  • Patent number: 6500374
    Abstract: The present invention provides a method for manufacturing a rare-earth bonded magnet as follows: A compound 10, prepared by pelletizing a kneaded mixture of a rare-earth-bonded-magnet composition containing a rare-earth magnet powder, a binder resin and an antioxidant, is stored in a hopper 91, and fed into a cylinder 3 through a feeding pipe 92. Meanwhile, piston 81 is extended by driving an oil-hydraulic cylinder 8, and moved downward to compact the compound 10 fed into the cylinder 3 while gradually transferring the compound downward inside the cylinder 3. The cylinder 3 and a heating portion 41 are heated by heaters 5, the compound 10 passing therethrough is heated to become a melted material 11, and the melted material 11 is continuously extruded out from a die 4 in the downward-vertical direction, and is then cooled and solidified when passing through a tip portion 43, thus obtaining a molded body 12 of a rare-earth-bonded-magnet.
    Type: Grant
    Filed: February 26, 1999
    Date of Patent: December 31, 2002
    Assignee: Seiko Epson Corporation
    Inventors: Koji Akioka, Hayato Shirai, Ken Ikuma
  • Patent number: 6500530
    Abstract: A magnetic recording medium of the present invention comprises a first magnetic layer and a second magnetic layer each having different magnetization, coercive force, and temperature characteristics. By magnetically coupling the first and second magnetic layers to each other, gradual temperature dependence of magnetization can be realized.
    Type: Grant
    Filed: October 5, 1999
    Date of Patent: December 31, 2002
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shinzo Sawamura, Hiroyuki Katayama
  • Patent number: 6500551
    Abstract: The magnetic recording medium of the invention comprises a substrate and a magnetic layer stacked thereon and composed of a dispersion of a ferromagnetic powder in a binder, and is characterized in that the binder contains a polyurethane resin 1 obtained by polymerization of a diol compound having a cyclic structure and a long-chain form of alkyl chain with a diisocyanate compound. Preferably, the polyurethane resin contains as diol components a dimer diol and an aliphatic diol having a medium-chain form of alkyl branched chain. The polyurethane resin may comprise a polyether polyol having a cyclic structure. A dibasic acid in the polyester polyol may contain an aliphatic dibasic acid, the diol component may contain an aliphatic diol that does not include a cyclic structure having an alkyl branched chain, and an chain extender may include a polyester polyol comprising an aliphatic diol having an alkyl branched chain.
    Type: Grant
    Filed: March 21, 2000
    Date of Patent: December 31, 2002
    Assignee: Fuji Photo Film Co., LTD
    Inventors: Hiroshi Hashimoto, Yuichiro Murayama, Katsuhiko Meguro
  • Patent number: 6497948
    Abstract: The present invention aims to provide a particulate magnetic recording medium showing a high C/N in high-density magnetic recording (especially using an MR head for reproducing). Herein disclosed is a magnetic recording medium comprising a lower layer containing a nonmagnetic powder and a binder provided on a nonmagnetic flexible substrate and a magnetic layer containing a ferromagnetic powder and a binder provided thereon wherein said magnetic layer has an average thickness d of 0.01-0.1 &mgr;m, the ferromagnetic powder contained in said magnetic layer is an acicular ferromagnetic alloy powder having an average major axis length of 0.1 &mgr;m or less and a as of 120 A.m2/kg (120 emu/g) or less, the nonmagnetic powder contained in said lower layer is an acicular inorganic powder having an average major axis length of 0.15 &mgr;m or less, and said ferromagnetic powder has an aspect ratio equal to or smaller than the aspect ratio of said acicular inorganic powder.
    Type: Grant
    Filed: March 29, 2001
    Date of Patent: December 24, 2002
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Kiyomi Ejiri, Masahiko Mori
  • Patent number: 6495252
    Abstract: High bit density, longitudinal and/or perpendicular magnetic recording media that are substantially free of Barkhausen noise are fabricated by utilizing magnetically soft, superparamagnetic underlayers which are compatible with the grain structure of the magnetic recording layer and serve to guide magnetic flux through the magnetic layer. An exchange de-coupling layer is positioned between the superpararnagnetic underlayer and the magnetic layer for prevention of direct coupling of the grains of each the layers.
    Type: Grant
    Filed: July 19, 2000
    Date of Patent: December 17, 2002
    Assignee: Seagate Technology LLC
    Inventors: Hans J. Richter, Samuel Dacke Harkness
  • Patent number: 6482506
    Abstract: Provided is a particulate magnetic recording medium having excellent electromagnetic characteristics, especially, a particulate magnetic recording medium which achieves a high output and a low noise and which is suitable for reproduction with an MR head. A magnetic recording medium comprising a flexible nonmagnetic support having thereon, in order, a nonmagnetic layer containing a nonmagnetic powder and a binder and at least two magnetic layers including an uppermost magnetic layer and a lowermost magnetic layer, each containing a ferromagnetic powder and a binder, wherein said at least two magnetic layers have a total thickness of from 0.02 &mgr;m to 0.5 &mgr;m and an average particle volume V(u) and a saturation magnetization &sgr;s(u) of a ferromagnetic powder in said uppermost magnetic layer are, respectively, higher than an average particle volume V(L) and a saturation magnetization &sgr;s(L) of a ferromagnetic powder in said lowermost magnetic layer.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: November 19, 2002
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Kiyomi Ejiri, Masahiko Mori
  • Patent number: 6483645
    Abstract: An optical isolator comprsing at least two parts of a Faraday rotator obtained from a garnet crystal and an analyzer, which is small in size, can be mounted directly to a semiconductor laser. The garnet crystal is grown, by a liquid-phase epitaxial growth technique, on the substrate of a garnet with a lattice constant of 12.514±0.015 Å, and consists of the following composition formula: (Tb1−(a+b+c+d)LnaBibM1cEud)3(Fe1−eM2e)5O12 where Ln is an element selected from rare-earth elements excluding Tb and Eu, and Y; M1 is an element selected from elements Ca, Mg, and Sr; M2 is an element selected from elements of Al, Ga, Sc, In, Ti, Si, and Ge; a, b, c, d, and e are defined as 0≦a≦0.5, 0.3<b≦0.6, 0≦c≦0.02, 0<d≦0.3, and 0.01<e≦0.3, respectively.
    Type: Grant
    Filed: October 11, 2000
    Date of Patent: November 19, 2002
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Masayuki Tanno, Satoru Fukuda
  • Patent number: 6479096
    Abstract: A GMR spin valve is provided for reading a magnetic signal from a magnetic recording medium. The spin valve includes a non-magnetic layer such as for example copper, separated by first and second magnetic layers. The spin valve includes a pinned magnetic layer and a free magnetic layer, the resistance of the spin valve changing with the relative angle between the direction of magnetization of free and pinned layers. Extremely smooth surfaces are provided at the interfaces between the non-magnetic layer and the adjacent magnetic layers. This smooth interface greatly enhances the performance and reliability of the spin valve by allowing extremely tight control of the thickness of the non-magnetic layer and by preventing atomic diffusion between the non-magnetic and magnetic layers. This smooth interface is achieved by including a surfactant in the deposition of the non-magnetic layer.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: November 12, 2002
    Assignee: Read-Rite Corporation
    Inventors: Zhupei Shi, Ming Mao, Qunwen Leng
  • Patent number: 6475598
    Abstract: The present invention provides a magnetic recording medium exhibiting a high C/N ratio as well as having excellent running durability even under high-density magnetic recording. Disclosed is a magnetic recording medium comprising, on either side of a flexible nonmagnetic support, a nonmagnetic layer containing a nonmagnetic powder and a binder and a magnetic layer containing a ferromagnetic powder and a binder in this order, having an average thickness of said magnetic layer of from 0.01 to 0.3 &mgr;m and a total average thickness of said magnetic layer and said nonmagnetic layer of from 0.1 to 1.0 &mgr;m, characterized in that the number of projections having a height equal to or higher than 20 nm on the magnetic layer surface measured with AFM (Atomic Force Microscope) is equal to or less than 100 pieces per 30 &mgr;m×30 &mgr;m square as well as the PSD (Power Spectrum Density) of the magnetic layer surface measured with the AFM is equal to or less than 0.
    Type: Grant
    Filed: June 23, 2000
    Date of Patent: November 5, 2002
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Koji Naoe, Kiyomi Ejiri, Masahiko Mori
  • Patent number: 6475613
    Abstract: The invention provides a magnetic recording medium which is reduced in the occurrence of a dropout and has excellent durability. The magnetic recording medium comprises a magnetic layer on one surface of a non-magnetic support and a back-coat layer, containing mainly a non-magnetic powder and a binder, on the other surface. The back-coat layer includes (a) a carbon black having an average particle size of 15 to 25 nm, (b) a carbon black having an average particle size of 60 to 80 nm and (c) CaCO3 and/or BaSO4 having an average particle size of 30 to 75 nm as the non-magnetic powder. The back-coat layer preferably includes said carbon black (a), said carbon black (b) and said CaCO3 and/or BaSO4 (c) in a ratio of (a)/(b)/(c)=60-80/3-15/15-30 by weight.
    Type: Grant
    Filed: April 24, 2000
    Date of Patent: November 5, 2002
    Assignee: TDK Corporation
    Inventors: Tsutomu Ide, Akira Saitoh
  • Patent number: 6475611
    Abstract: A multilayer superlattice having a structure with many interfaces of magnetic/non-magnetic layers could increase the coercivity of a magnetic recording medium by increasing the interfacial anisotropy. A Si-containing seedlayer between a soft underlayer and the multilayer superlattice further boosts the coercivity of the magnetic recording medium.
    Type: Grant
    Filed: August 7, 2000
    Date of Patent: November 5, 2002
    Assignee: Seagate Technology LLC
    Inventor: Ga-Lane Chen
  • Publication number: 20020160195
    Abstract: Metal Nanoshells having partial coverage of a substrate or core particle and methods of making them are provided. A method of making a partial metal nanoshell preferably includes asymmetrically confining a substrate particle and selectively layering a metallic material over the substrate particle according to the asymmetry. Confining the substrate particle may include attaching it to a support defining an exposed portion and a contact portion. The method may include either chemically modifying the substrate particle. The solid angle of coverage of the partial metal nanoshell may be influenced by the nature of the chemical modification, such as alternatives of activating and passivating the exposed portion.
    Type: Application
    Filed: November 5, 2001
    Publication date: October 31, 2002
    Inventors: Nancy J. Halas, Robert K. Bradley
  • Patent number: 6472063
    Abstract: A magnetic recording medium comprising at least a lower non-magnetic layer containing at least a non-magnetic powders and a binder resin formed on a non-magnetic support and an upper magnetic layer formed on the lower non-magnetic layer, wherein the magnetic recording medium is used for a recording-reproducing system in which recorded signals are reproduced by an MR head, and a plastic deformation hardness Hv from the upper magnetic layer surface to an indentation depth of 0.1 &mgr;m is 100 to 200 mgf/&mgr;m2and a Young's modulus E in a thickness direction from the upper magnetic layer surface to the indentation depth of 0.1 &mgr;m is 2000 to 3000 mgf/&mgr;m2.
    Type: Grant
    Filed: September 12, 2000
    Date of Patent: October 29, 2002
    Assignee: TDK Corporation
    Inventor: Shigeharu Watase
  • Patent number: 6468614
    Abstract: An apparatus for displaying paper, fabric, photographs or the like, comprises a long, narrow strip of thin ferromagnetic spring steel, and a number of small tacks embedded with rare earth magnets or other magnets. A tape-like dispenser stores unused tacks and a portion of the strip that has yet to be used. The strip of spring steel is covered on one face by a strong adhesive. The adhesive side, when the strip has not been used, is covered by a protective layer, such as wax paper. The spring steel is rolled up inside the dispenser. The strip may be divided at regular intervals by a cut through the protective paper and adhesive layer, the cut line scoring the spring steel.
    Type: Grant
    Filed: March 17, 2000
    Date of Patent: October 22, 2002
    Inventors: Anna L. LeVine, Kermit S. Westergaard
  • Patent number: 6468678
    Abstract: Magnetic, conformable articles for use with traffic bearing surfaces are disclosed which comprise an organic binder having magnetic particles distributed therein. The articles may be employed in intelligent vehicle guidance systems, and in systems to guide other mobile objects such as farm animals, pets, or visually impaired pedestrians. Methods of making the articles and methods of using the systems to control and/or guide a mobile object using the magnetic field generated from the articles are also described.
    Type: Grant
    Filed: October 22, 1997
    Date of Patent: October 22, 2002
    Assignee: 3M Innovative Properties Company
    Inventors: Thomas J. Dahlin, Gregory F. Jacobs, David M. Hopstock, Robert L. Keech, Richard E. Fayling, Richard G. Newell, Claud M. Lacey, Bernard A. Gonzalez
  • Patent number: 6468624
    Abstract: The invention is a hook fastener strip (10), having magnetically attractable wires (13a,b,c,&d) which are located between, and retained by, hook members (11) on the front face of the fastener strip (10). Each hook member (11) is comprised of a shaft (14) and a split-mushroom-shaped head (15). The outer edges of head (15) protrude beyond the sides of shaft (14), and the undersides of the outer edges form ledges (16a&b) which serve to retain the magnetically attractable wires (13a,b,c,&d) within the hook layer of the fastener strip (10). The magnetically attractable wires (13a,b,c,&d) within the fastener strip allow it to be secured to a correspondingly magnetically attractive object.
    Type: Grant
    Filed: November 20, 2000
    Date of Patent: October 22, 2002
    Assignee: YKK Corporation of America
    Inventors: Nobuo Fujisawa, Craig Jay Graham, Tsuyoshi Minato Minato, John Alexander Galbreath
  • Patent number: 6468666
    Abstract: A magnetically active laminate is disclosed. The magnetically active laminate is composed of a resin impregnated layer bonded to a distinct, magnetically active sheet. The laminate is especially well suited for use in the construction of erasable markerboards and cubicle panels, although many applications are possible within the scope of the present invention.
    Type: Grant
    Filed: November 22, 1999
    Date of Patent: October 22, 2002
    Assignee: Premark RWP Holdings, Inc.
    Inventors: Robert R. Krebs, Ernest L. Phelps
  • Patent number: 6461741
    Abstract: A high permeability grain-oriented electromagnetic steel sheet with a higher tension-imparting effect and more excellent cohesion and magnetic properties compared to the prior art, which also maintains sufficient corrosion resistance to withstand practical use; the grain-oriented electromagnetic steel sheet has on its surface an insulation coating comprising a first layer composed mainly of a divalent or trivalent metal hydrogen phosphate salt and silica, and a second layer composed mainly of aluminum borate and leaving a surface roughness of 0.1 &mgr;m-0.35 &mgr;m in terms of Ra (center like average roughness).
    Type: Grant
    Filed: September 13, 2000
    Date of Patent: October 8, 2002
    Assignee: Nippon Steel Corporation
    Inventors: Kazutoshi Takeda, Shuichi Yamazaki, Hideyuki Kobayashi, Hiroyasu Fujii
  • Patent number: 6461750
    Abstract: A magnetic recording media is formed with high in-plane coercivity employing dual magnetic layers. The first magnetic layer is sputter deposited in a chamber employing a shield such that the minimum incident angle of impinging atoms is relatively large, e.g., greater than about 26°. Embodiments of the present invention comprise depositing a NiAl seedlayer, a Cr or Cr alloy underlayer and a first CoCrTa magnetic layer at a thickness less than about 50Å for inducing the preferred (10.0) crystallographic orientation in the subsequently deposited second magnetic layer, e.g., CoCrPtTa or CoCrPtTaNb having a high Cr content of about 16 to about 21 at. %.
    Type: Grant
    Filed: September 28, 1999
    Date of Patent: October 8, 2002
    Assignee: Seagate Technology, Inc.
    Inventors: Qixu (David) Chen, Lin Huang, Charles Leu, Rajiv Yadav Ranjan
  • Patent number: 6458432
    Abstract: A process for producing a magnetic disk having a randomly oriented magnetic powder, comprises: applying a magnetic coating solution containing at least a magnetic powder to a web that is being continuously conveyed, so as to prepare a magnetic layer; applying a first external magnetic field to the magnetic layer while the magnetic layer is wet; and applying a second external magnetic field to the magnetic layer while the magnetic layer is wet, wherein: the first external magnetic field is applied with a set of a first pair of same-pole-opposed magnets with the web interposed therebetween and a second pair of same-pole-opposed magnets with the web interposed therebetween; the first and second pairs are provided on the same plane of the web and on two equal sides of an isosceles triangle so that a perpendicular line dropped from a base of the isosceles triangle forms a line perpendicular to a conveying direction of the web; and the second external magnetic field is an alternating magnetic field, and is applied
    Type: Grant
    Filed: November 26, 2001
    Date of Patent: October 1, 2002
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Hitoshi Noguchi, Junichi Nakamikawa, Shinji Saito
  • Patent number: 6455174
    Abstract: A magnetic recording medium comprises, on a substrate, a recording auxiliary layer, a recording holding layer, recording control layer, and a recording layer. The recording layer is constructed by using a ferri-magnetic material having perpendicular magnetization. The data can be recorded at a super high density by using the recording and reproducing head of the present invention, because the recording layer has the perpendicular magnetization. The disappearance of data, which would be otherwise caused by the thermomagnetic relaxation phenomenon, is suppressed after recording the data, because the recording layer has large coercive force at the room temperature. The data, which is recorded at the super high density on the magnetic recording medium, can be reproduced by using a magnetic resistance element carried on the recording and reproducing head.
    Type: Grant
    Filed: November 3, 1999
    Date of Patent: September 24, 2002
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Hiroki Takao, Yuji Yamazaki, Susumu Imai, Hiroyuki Awano, Katsusuke Shimazaki
  • Patent number: RE38048
    Abstract: There is provided a magnetic recording medium which comprises a substrate, a magnetic layer on one surface of a substrate and a backcoating layer on the other surface of the substrate, wherein the magnetic layer contains a magnetic metal powder having a major axis of not larger than 0.2 &mgr;m and an inorganic powder having a Mohs' hardness of at least 5, and the backcoating layer contains an inorganic powder having a particle size smaller than the size of the major axis of the magnetic metal powder and which has sufficiently reduced noise at high density recording and high output required in, for example, a small size video tape with high picture quality, the magnetic recording medium in the form of a magnetic tape having a total thickness of not larger than 14 &mgr;m inclusive of the substrate, the magnetic layer and the backcoating layer, and reliably maintained not to increase the noise after long term storage.
    Type: Grant
    Filed: July 2, 1998
    Date of Patent: March 25, 2003
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Seigi Kawarai, Kenichiro Yoshida, Akira Kato