Magnetic Recording Medium Or Device Formed Patents (Class 427/548)
  • Patent number: 9175137
    Abstract: A method for curing a macromolecular cyanurate network. The method of curing includes suspending a plurality of functionalized silica-coated magnetic nanoparticles in a resin mixture, which includes cyanate ester monomers, cyanate ester oligomers, or both. After a static magnetic field is applied to the plurality of functionalized silica-coated magnetic nanoparticles in the resin mixture, an alternating electromagnetic field (having frequency ranging from about 1 kHz to about 10 MHz) is imposed for a cure time.
    Type: Grant
    Filed: November 25, 2013
    Date of Patent: November 3, 2015
    Assignee: The United States of America as represented by the Secretary of the Air Force
    Inventors: Christopher Sahagun, Andrew Guenthner, Joseph Mabry
  • Publication number: 20150147481
    Abstract: A method for making a scissoring type current-perpendicular-to-the-plane magnetoresistive sensor with exchange-coupled soft side shields uses oblique angle ion milling to remove unwanted material from the side edges of the upper free layer. All of the layers making up the sensor stack are deposited as full films. The sensor stack is then ion milled to define the sensor side edges. The side regions are then refilled by deposition of an insulating layer. Next, the lower soft magnetic layers of the exchange-coupled side shields are deposited, which also coats the insulating layer up to and past the side edges of the upper free layer. The soft magnetic material adjacent the side edges of the upper free layer is removed by oblique angle ion beam milling. The material for the antiparallel-coupling (APC) layers is deposited, followed by deposition of the material for the upper soft magnetic layers of the exchange-coupled side shields.
    Type: Application
    Filed: November 20, 2013
    Publication date: May 28, 2015
    Applicant: HGST Nertherlands B..V.
    Inventors: Patrick Mesquita Braganca, Jordan Asher Katine, Neil Smith
  • Publication number: 20150125623
    Abstract: Methods for forming a nanoparticle assembly are generally provided. The method can comprise applying a colloidal fluid to a surface of a magnetic media, wherein the colloidal fluid comprises magnetic nanoparticles, a surfactant, a trigger salt, and a carrier medium; and assembling the magnetic nanoparticles into a pattern through a magnetic force arising from the surface of the magnetic media.
    Type: Application
    Filed: November 7, 2014
    Publication date: May 7, 2015
    Inventors: Thomas M. Crawford, Longfei Ye, Tanner G. Pearson, O. Thompson Mefford, Yves Cordeau
  • Patent number: 8993073
    Abstract: An embodiment of the invention relates to a perpendicular magnetic recording medium comprising (1) a substrate, (2) an interlayer comprising hexagonal columns and (3) a magnetic layer, wherein the magnetic layer is deposited applying a bias voltage to the substrate such that the magnetic layer comprises magnetic grains having substantially no sub-grains within the magnetic layer, and the magnetic layer has perpendicular magnetic anisotropy.
    Type: Grant
    Filed: July 14, 2008
    Date of Patent: March 31, 2015
    Assignee: Seagate Technology LLC
    Inventors: Weilu Xu, Miaogen Lu, Mariana R. Munteanu, Michael Z. Wu, Shanghsien Alex Rou, Steve Kuo-Hsing Hwang, Ed Yen
  • Publication number: 20150079361
    Abstract: Methods for forming a multi-layered nanoscale structure by forming a stack of individual polymeric layers on a substrate are provided. Each individual polymeric layer comprises a cured polymeric material immobilizing a pattern of magnetic nanoparticles. The pattern of magnetic nanoparticles can be different within each individual polymeric layer due to their nature of formation.
    Type: Application
    Filed: September 17, 2014
    Publication date: March 19, 2015
    Inventor: Thomas Crawford
  • Publication number: 20140106182
    Abstract: A sub-structure, suitable for use as a hot seed on which to form a perpendicular magnetic main write pole, is described. It is made up of a buffer layer of atomic layer deposited alumina on which there are one or more seed layers having a body-centered cubic (bcc) crystal structure. Finally, the high coercivity magnetic film lies on the seed layer(s). It is critical that the high coercivity magnetic film be deposited at a very low deposition rate (around 1 Angstrom per second).
    Type: Application
    Filed: October 14, 2012
    Publication date: April 17, 2014
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Shengyuan Wang, Kunliang Zhang, Min Li
  • Patent number: 8685549
    Abstract: A nanocomposite article that includes a single-crystal or single-crystal-like substrate and heteroepitaxial, phase-separated layer supported by a surface of the substrate and a method of making the same are described. The heteroepitaxial layer can include a continuous, non-magnetic, crystalline, matrix phase, and an ordered, magnetic magnetic phase disposed within the matrix phase. The ordered magnetic phase can include a plurality of self-assembled crystalline nanostructures of a magnetic material. The phase-separated layer and the single crystal substrate can be separated by a buffer layer. An electronic storage device that includes a read-write head and a nanocomposite article with a data storage density of 0.75 Tb/in2 is also described.
    Type: Grant
    Filed: November 30, 2010
    Date of Patent: April 1, 2014
    Assignee: UT-Battelle, LLC
    Inventors: Amit Goyal, Junsoo Shin
  • Publication number: 20140037861
    Abstract: A perpendicular magnetic recording (PMR) head is fabricated with main pole and a trailing edge shield antiferromagnetically coupled across a write gap by either having the write gap layer formed as a synthetic antiferromagnetic tri-layer (SAF) or formed as a monolithic layer of antiferromagnetic material. The coupling improves the write performance of the writer by enhancing the perpendicular component of the write field and its gradient. Methods of fabricating the writer are provided.
    Type: Application
    Filed: October 8, 2013
    Publication date: February 6, 2014
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Tai Min, Tang Yuhui, Lijie Guan
  • Patent number: 8617643
    Abstract: A method of producing a nanoscale structure having substantially immobilized nanoparticles arranged at a predetermined patterned is generally disclosed. First, a curable polymeric solution is placed within a well defined by a wafer. The curable polymeric solution includes a curable polymeric material and a magnetically coated nanoparticle. The well is positioned adjacent to an atomically-smooth medium. A recording head is moved in a predetermined manner to produce a magnetic field profile that substantially immobilizes the magnetically coated nanoparticle within the curable polymeric solution in the well. The curable polymeric solution is cured such that the magnetically coated nanoparticle remains substantially immobilized after the magnetic field profile is removed.
    Type: Grant
    Filed: October 1, 2007
    Date of Patent: December 31, 2013
    Assignee: University of South Carolina
    Inventor: Thomas M. Crawford
  • Patent number: 8619467
    Abstract: Multi-period structures exhibiting giant magnetoresistance (GMR) are described in which the exchange coupling across the active interfaces of the structure is ferromagnetic.
    Type: Grant
    Filed: February 18, 2011
    Date of Patent: December 31, 2013
    Assignee: Integrated Magnetoelectronics
    Inventors: E. James Torok, Richard Spitzer, David L. Fleming, Edward Wuori
  • Publication number: 20130011575
    Abstract: An apparatus and associated method for reorienting the magnetic anisotropy of magnetic recording discs. A pallet that is moveable along a path of travel is also sized to selectively hold either a first magnetic recording disc of a first size or a second magnetic recording disc of a second size different than the first size. A first processing chamber in the path of travel is adapted for forming a soft underlayer (SUL) of magnetic material with non-radially oriented magnetic anisotropy on a substrate corresponding to one of the first and second magnetic recording discs. A second processing chamber in the path of travel downstream of the first processing chamber is adapted for selectively re-orienting the SUL's magnetic anisotropy via a magnetic source emanating a first magnetic field if the substrate corresponds to the first magnetic recording disc and emanating a different second magnetic field if the substrate corresponds to the second magnetic recording disc.
    Type: Application
    Filed: September 14, 2012
    Publication date: January 10, 2013
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Paul S. McLeod, Charles F. Brucker, Jeffrey S. Reiter
  • Publication number: 20120295133
    Abstract: A perpendicular magnetic recording (PMR) head is fabricated with main pole and a trailing edge shield antiferromagnetically coupled across a write gap by either having the write gap layer formed as a synthetic antiferromagnetic tri-layer (SAF) or formed as a monolithic layer of antiferromagnetic material. The coupling improves the write performance of the writer by enhancing the perpendicular component of the write field and its gradient. Methods of fabricating the writer are provided.
    Type: Application
    Filed: May 16, 2011
    Publication date: November 22, 2012
    Inventors: Tai Min, Yuhui Tang, Lijie Guan, Min Li
  • Patent number: 8263191
    Abstract: There is described a method of producing color effect images on a carrier substrate, wherein it is provided that a latent magnetic image comprising magnetic pixels and non-magnetic pixels is produced on a magnetizable printing form, a carrier substrate with a decorative layer applied to the carrier substrate and provided with non-spherical, preferably needle-form or flake-form magnetic color effect pigments is moved past the magnetizable printing form so that color effect pigments of the decorative layer are changed in their orientation relative to the carrier substrate by the field line image produced by the magnetic pixels of the magnetizable printing form, and the color effect pigments are fixed in the decorative layer in the orientation which is changed by the field line image of the printing form. There is further described an apparatus for carrying out the method and a multi-layer body produced therewith.
    Type: Grant
    Filed: April 26, 2006
    Date of Patent: September 11, 2012
    Assignee: Leonhard Kurz Stiftung & Co. KG
    Inventor: Heinrich Wild
  • Patent number: 8147925
    Abstract: A pattern is formed by applying a coating composition containing magnetic particles to an article so that a coating film is formed, and a plurality of sheet form magnets are placed along the front surface of this coating film. Adjacent sheet form magnets are arranged in such a state that the magnetic poles on the front surface and the magnetic poles on the back surface are different between adjacent sheet form magnets, and side surfaces of the sheet form magnets contact each other. The coating composition contains a thermoplastic resin, magnetic particles with flaky form and a specific low boiling point solvent and a specific high boiling point solvent. A magnetic field is applied to the coating film by the sheet form magnets, so that the magnetic particles in the coating film are oriented by the magnetic field and the magnetic particles are oriented substantially parallel to the front surface of the coating film above the contact portions between the sheet form magnets.
    Type: Grant
    Filed: April 5, 2007
    Date of Patent: April 3, 2012
    Assignees: Inoac Corporation, Ju Teng International Holdings Ltd., Sang Broli Company Limited
    Inventors: Yoshinori Sugiura, Jun Nishikawa, Ryoichi Nakaoka, Chika Kanada, Akito Harada
  • Patent number: 8048492
    Abstract: A magnetoresistive effect element is produced by forming a first magnetic layer, a spacer layer including an insulating layer and a conductive layer which penetrates through the insulating layer and passes a current, on the first magnetic layer, and a second magnetic layer all of which or part of which is treated with ion, plasma or heat, on the formed spacer layer.
    Type: Grant
    Filed: December 20, 2006
    Date of Patent: November 1, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Hiromi Yuasa, Yoshihiko Fuji, Hitoshi Iwasaki
  • Publication number: 20110244114
    Abstract: Magnetic storage media and methods for constructing magnetic storage media that include a multilayer structure are described. In some examples, a magnetic recording medium can be formed by forming an underlayer over a substrate, drying the underlayer, milling a plurality of magnetic particles, and forming a magnetic layer that includes the plurality of magnetic particles over the underlayer. The magnetic particles may be selected from the group consisting of magnetic platelet-shaped particles and magnetic particles with an aspect ratio less than or equal to approximately 1.5. In addition, the milling process may include milling the plurality of magnetic particles so a magnetic medium formed in the absence of an applied magnetic field exhibits a longitudinal squareness less than or equal to approximately 0.40.
    Type: Application
    Filed: April 2, 2010
    Publication date: October 6, 2011
    Applicant: Imation Corp.
    Inventors: David C. Lowery, Stephen R. Ebner, Bruce H. Edwards, Ryosuke Isobe, Larold L. Olson, Michael P. Sharrock, Scott A. Walker
  • Publication number: 20110205668
    Abstract: A magnetic recording medium comprises a data region for recording data and a servo region that is disposed adjacent to the data region and has recorded information for controlling a magnetic head. The data region has a pattern of dots separated from each other by grooves or nonmagnetic material. The servo region lacks the pattern of dots, and includes magnetic information written in a flat region. The magnetic recording medium can be formed by a method that does not need a separate process of writing servo information.
    Type: Application
    Filed: December 9, 2010
    Publication date: August 25, 2011
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Shinji UCHIDA
  • Patent number: 7842334
    Abstract: A magnetic sensor includes a single substrate, a conventional GMR element formed of a spin-valve film including a single-layer-pinned fixed magnetization layer, and a SAF element formed of a synthetic spin-valve film including a plural-layer-pinned fixed magnetization layer. When the spin-valve film intended to act as the conventional GMR element and the synthetic spin-valve film intended to act as the SAF element are subjected to the application of a magnetic field oriented in a single direction at a high temperature, they become giant magnetoresistive elements whose magnetic-field-detecting directions are antiparallel to each other. Since films intended to act as the conventional GMR element and the SAF element can be disposed close to each other, the magnetic sensor which has giant magnetoresistive elements whose magnetic-field-detecting directions are antiparallel to each other can be small.
    Type: Grant
    Filed: February 6, 2008
    Date of Patent: November 30, 2010
    Assignee: Yamaha Corporation
    Inventors: Yukio Wakui, Masayoshi Omura
  • Patent number: 7726008
    Abstract: A magnetic-field sensor device comprises at least two electrodes; an insulating layer separating the at least two electrodes; at least one layer of chemically-synthesized magnetic nanoparticles disposed at or above a level with the insulating layer, and disposed between the at least two electrodes; and an organic spacer surrounding each of the chemically-synthesized magnetic nanoparticles. A deviation between diameters of different ones of the nanoparticles is less than 15%. Moreover, the chemically-synthesized magnetic nanoparticles range in size between 2 nm and 20 nm in diameter.
    Type: Grant
    Filed: January 7, 2005
    Date of Patent: June 1, 2010
    Assignee: International Business Machines Corporation
    Inventors: Charles T. Black, Stephen M. Gates, Christopher B. Murray, Robert L. Sandstrom
  • Patent number: 7703811
    Abstract: The current invention relates to a security element for security substrates, such as those used for banknotes and the like, having enhanced public recognition, anti-counterfeit and detection properties. A security element comprising an elongate strip of a light transmitting polymeric substrate, said substrate being provided with a magnetic feature and a metallic design, the metallic design being provided by a combination of metal and non-metallic regions and comprising indicia, characters, patterns, designs, or geometrical shapes or a combination of the aforesaid design comprising at least one repeating pattern or which one or more of the frequency, the instantaneous amplitude and/or the maximum amplitude of the pattern varies along the length of the element, said pattern being positioned relative to the magnetic feature such that it does not overlap therewith.
    Type: Grant
    Filed: January 9, 2004
    Date of Patent: April 27, 2010
    Assignee: De La Rue International, Ltd.
    Inventor: Roland Isherwood
  • Publication number: 20090195904
    Abstract: The invention relates to a method of manufacturing a device (10) comprising a layer (12) having a pattern of disjunct portions (14) of magnetic material (18) generating a corresponding pattern of local magnetic fields (2). The magnetic material (18) is constituted of particles (22) dispersed in a solid substance (24). The particles are magnetically stable and substantially aligned for generating the local magnetic fields (2). The method comprises the steps of: providing a substance (32) having the particles (22) dispersed in the substance (32), the substance (32) having a viscosity for allowing the particles (22) to move in the substance (32), creating the pattern of disjunct portions (14) of the substance (32) in the layer (12) of the device (10), applying an external magnetic field (50) for substantially aligning the particles (22) in the disjunct portions (14) of the substance (32), and solidifying the substance (32) for obtaining the solid substance (24).
    Type: Application
    Filed: July 13, 2006
    Publication date: August 6, 2009
    Applicant: NXP B.V.
    Inventors: Jaap Ruigrok, Marcello L., M. Balistreri, Antonius E., T. Kuiper, Michel M., J. Decre
  • Publication number: 20090061106
    Abstract: A perpendicular magnetic memory medium capable of high-density recording and reproducing consists of a soft magnetic lining layer (12), a non-magnetic middle layer (13), a recording layer (14) that is formed by arranging hard magnetic nanoparticles (17), an overcoat layer (15), and a lubricous layer (16), all of which are arranged on a substrate (11) in this sequence, wherein an average diameter of the nanoparticles ranges between 2 nm and 10 nm, a standard deviation of diameters of the nanoparticles is 10% or less of the average diameter of the nanoparticles, and an average interval of the nanoparticles is between 0.2 nm and 5 nm, and an magnetic easy axis of the recording layer 14 is perpendicular to a face of the substrate (11), such that high-density recording and reproducing is realized by the perpendicular magnetic medium.
    Type: Application
    Filed: October 27, 2008
    Publication date: March 5, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Nobutaka Ihara, Hiroyoshi Kodama, Takuya Uzumaki
  • Publication number: 20090008922
    Abstract: The invention relates to a security element for protecting documents of value, which has magnetic material. Furthermore, the invention relates to a document of value, a transfer material and method for producing such security elements and documents of value as well as a method and an apparatus for checking such a security element or document of value. According to the invention the security element has at least two magnetic materials, wherein the magnetic materials have different coercive field strengths and are applied onto and/or incorporated in the security element in such a manner that their remanence is equally high.
    Type: Application
    Filed: October 11, 2005
    Publication date: January 8, 2009
    Inventors: Jurgen Schutzmann, Lothar Schutt
  • Publication number: 20070237891
    Abstract: A pattern is formed by applying a coating composition containing magnetic particles to an article so that a coating film is formed, and a plurality of sheet form magnets are placed along the front surface of this coating film. Adjacent sheet form magnets are arranged in such a state that the magnetic poles on the front surface and the magnetic poles on the back surface are different between adjacent sheet form magnets, and side surfaces of the sheet form magnets contact each other. The coating composition contains a thermoplastic resin, magnetic particles with flaky form and a specific low boiling point solvent and a specific high boiling point solvent. A magnetic field is applied to the coating film by the sheet form magnets, so that the magnetic particles in the coating film are oriented by the magnetic field and the magnetic particles are oriented substantially parallel to the front surface of the coating film above the contact portions between the sheet form magnets.
    Type: Application
    Filed: April 5, 2007
    Publication date: October 11, 2007
    Applicants: INOAC CORPORATION, SANG BROLI COMPANY LIMITED
    Inventors: Yoshinori Sugiura, Jun Nishikawa, Ryoichi Nakaoka, Chika Kanada, Akito Harada
  • Patent number: 7258900
    Abstract: A magnetic field is applied to planarize magnetic pigment flakes relative to a surface. Pigment flakes, such as optically variable pigment flakes, are used in a variety of paints, inks, extrusions, powder coatings, and other forms for decorative and security applications. In many applications pigment flakes tend to align parallel to each other and to the surface to which they are applied. If the pigment flakes include a suitable magnetic structure, a magnetic field can be applied to subsequently align the flakes or enhance the alignment of the flakes in the plane of the substrate if the carrier that the flakes are dispersed in is still fluid. In some printing operations, pigment flakes that are applied parallel to the substrate are pulled out of plane when the print screen or printing die is lifted off the substrate. Application of a magnetic field can re-align pigment flakes to the plane of the substrate, enhancing the visual quality of the printed image, especially with optically variable pigments.
    Type: Grant
    Filed: November 13, 2002
    Date of Patent: August 21, 2007
    Assignee: JDS Uniphase Corporation
    Inventors: Vladimir P. Raksha, Charles T. Markantes, Dishuan Chu, Paul G. Coombs
  • Patent number: 7203607
    Abstract: A method for estimating the average intergranular exchange field using measurements of major and minor hysteresis loops. The method also facilitates deshearing hysteresis loops for analysis purposes in perpendicular media. This estimation technique is especially important for modern perpendicular media because exchange plays a critical role and process control can be difficult.
    Type: Grant
    Filed: November 12, 2004
    Date of Patent: April 10, 2007
    Assignee: Hitachi Global Storage Technologies
    Inventor: James Terrence Olson
  • Patent number: 7112354
    Abstract: An apparatus includes a low magnetic-coercivity layer of material (LMC layer) having a majority electron-spin-polarization (M-ESP), an energy-gap coupled with the LMC layer, wherein a flow of spin-polarized electrons having an electron-spin-polarization anti-parallel to the LMC layer are injected via the energy-gap, to change the M-ESP of the LMC layer. A non-magnetic material is in electrical communication with the LMC layer and provides a spin-balanced source of current to the LMC layer, responsive to the injection of spin-polarized electrons into the LMC layer.
    Type: Grant
    Filed: February 3, 2005
    Date of Patent: September 26, 2006
    Assignee: Intel Corporation
    Inventors: Eric C. Hannah, Michael A. Brown
  • Patent number: 7072209
    Abstract: A magnetic memory element includes a sense structure, a tunnel barrier adjacent the sense structure, and a synthetic antiferromagnet (SAF) adjacent the tunnel barrier on a side opposite the sense structure. The SAF includes an antiferromagnetic structure adjacent a ferromagnetic seed layer. The ferromagnetic seed layer provides a texture so that the antiferromagnetic structure deposited on the ferromagnetic seed layer has reduced pinning field dispersion.
    Type: Grant
    Filed: December 29, 2003
    Date of Patent: July 4, 2006
    Assignee: Micron Technology, Inc.
    Inventor: James G. Deak
  • Patent number: 7022383
    Abstract: Although it is known that exchange bias can be utilized in abutted junctions for longitudinal stabilization, a relatively large moment is needed to pin down the sensor edges effectively. Due to the inverse dependence of the exchange bias on the magnetic layer thickness, a large exchange bias has been difficult to achieve by the prior art. This problem has been solved by introducing a structure in which the magnetic moment of the bias layer has been approximately doubled by pinning it from both above and below through exchange with antiferromagnetic layers. Additionally, since the antiferromagnetic layer is in direct abutted contact with the free layer, it acts directly to help stabilize the sensor edge, which is an advantage over the traditional magnetostatic pinning that had been used.
    Type: Grant
    Filed: October 22, 2002
    Date of Patent: April 4, 2006
    Assignee: Headway Technologies, Inc.
    Inventors: Yun-Fei Li, Hui-Chuan Wang, Chyu-Jiuh Torng, Cherng-Chyi Han, Mao-Min Chen
  • Patent number: 6858328
    Abstract: A master information carrier with excellent durability is provided, for the use of static and a real lump-sum recording of digital information signals on magnetic recording medium. The master information carrier comprises a non-magnetic substrate on which a ferromagnetic film is disposed with an embossed pattern. Protrusions of the embossed pattern correspond to a disposition of the digital information signals. Recessed portions of the embossed pattern of the ferromagnetic film are filled with non-magnetic solid material. Alternately, A non-magnetic substrate has an embossed pattern and recessed portions of the embossed pattern correspond to a disposition of the digital information signals. A ferromagnetic film is filled in the recessed portions of the embossed pattern.
    Type: Grant
    Filed: March 18, 1999
    Date of Patent: February 22, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Tatsuaki Ishida, Kiyokazu Tohma, Keizo Miyata, Yoriko Takai, Taizou Hamada, Hiroshi Ryonai
  • Patent number: 6835450
    Abstract: Multilayer magnetic recording medium is suitable for high recording densities and the recording of digital data, has very good electromagnetic recording properties in the entire recording wavelength range and good mechanical properties and possesses a flat frequency response and which has at least one upper magnetic recording layer less than 0.5 &mgr;m thick and at least one lower layer which contains a magnetically soft pigment.
    Type: Grant
    Filed: April 6, 2001
    Date of Patent: December 28, 2004
    Assignee: Imation Corp.
    Inventors: Ronald John Veitch, Albert Kohl, Helmut Jakusch, Andreas Ilmer, Peter Heilmann, Ria Kress, Stefan Müller, Johannes Sandrock
  • Patent number: 6831802
    Abstract: A method of thermally bonding lubricant over a surface of a magnetic disk in a disk drive involves providing a heat source at an air bearing surface (ABS) of a magnetic head; causing the heat source to be energized to produce heat; and causing the magnetic head to be moved across a surface portion of a magnetic disk so that lubricant is thermally bonded over the surface portion from the heat produced by the heat source. Preferably, this lubricant bonding mode of operation is performed on a regular or periodic basis. Alternatively, the mode is activated based on a predetermined environmental condition (e.g. temperature or humidity) or from an external signal. In one example, the heat source is comprised of first and/or second pole pieces of the magnetic head through which an electrical current is passed.
    Type: Grant
    Filed: September 30, 2003
    Date of Patent: December 14, 2004
    Assignee: Hitachi Global Storage Technologies
    Inventors: Donald Ray Gillis, Andrei Khurshudov
  • Patent number: 6821574
    Abstract: A multiple layer magnetic recording medium exhibiting a marked increase in skirt signal-to-noise ratios, and a method of manufacturing such magnetic recording medium including the steps of forming a lower support layer and a magnetic layer on the substrate; transporting the magnetic recording medium on a non-magnetic carrier in a transport direction; exposing the magnetic recording medium to a first magnetic field of up to about 2500 gauss when the average percent solids of the multiple layers is less than 40% collectively, and exposing the magnetic recording medium to at least one additional magnetic field of from about 3500 to about 7000 gauss as the magnetic recording medium continues to transport when the average percent solids of said multiple layers is from about 43% to about 60% collectively, wherein the magnetic pigment particles in said magnetic layer are oriented in a longitudinal direction.
    Type: Grant
    Filed: February 14, 2003
    Date of Patent: November 23, 2004
    Assignee: Imation Corp.
    Inventors: Stephen R. Ebner, Guy Tadlock
  • Patent number: 6773765
    Abstract: Disclosed is a process for making a flexible magnet with an induced anisotropy, and in particular to a process for making a flexible anisotropic magnet by thermal spraying in the presence of an applied magnetic field. The method may be used to fabricate a substrate having a flexible anisotropic magnetic coating or a free standing anisotropic flexible magnet.
    Type: Grant
    Filed: November 4, 1999
    Date of Patent: August 10, 2004
    Assignee: The Research Foundation of State University of New York
    Inventors: Richard J. Gambino, Dongil Shin, Jeffrey A. Brogan
  • Patent number: 6764721
    Abstract: A perpendicular magnetic recording medium is formed of a soft magnetic layer, an anti-ferromagnetic layer, a magnetic recording layer, a protective layer, and a liquid lubricant layer deposited in that order on a non-magnetic substrate. The anti-ferromagnetic layer is a Mn alloy containing at least Co at 10 atomic % or greater and 50 atomic % or less or a Mn alloy containing at least Ir at 10 atomic % or greater and 30 atomic % or less. A radial magnetic field is applied during formation of the anti-ferromagnetic layer and the soft magnetic layer. Exchange coupling with the anti-ferromagnetic layer controls magnetic domain walls of the soft magnetic layer. The need for heat treatment after film formation is eliminated.
    Type: Grant
    Filed: October 20, 2003
    Date of Patent: July 20, 2004
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
  • Patent number: 6753043
    Abstract: A servo-patterned magnetic recording medium, comprising: a magnetic layer having a surface with substantially uniform topography, the magnetic layer including a data zone and a servo pattern, the servo pattern comprising: (a) a first patterned plurality of regions of first, higher values of magnetic coercivity Hc and magnetic remanence-thickness product Mrt; and (b) a second patterned plurality of ion-implanted regions of second, lower values of Hc. and Mrt; wherein the second, lower values of Hc and Mrt are sufficiently lower than the first, higher values of Hc and Mrt as to permit sensing for enabling accurate positioning of a read/write transducer head in the data zone but sufficiently high for providing the medium with thermal stability, high amplitude of magnetic transition, and high signal-to-noise ratio.
    Type: Grant
    Filed: October 12, 2001
    Date of Patent: June 22, 2004
    Assignee: Seagate Technology LLC
    Inventors: David S. Kuo, Xinwei Li
  • Patent number: 6716489
    Abstract: A manufacturing method of a domain wall displacement type magneto-optical recording medium comprises the steps of depositing a magnetic layer on a substrate to prepare a disc, and irradiating the magnetic layer with a converged light beam while applying a magnetic field and annealing the magnetic layer a converged light beam between information tracks.
    Type: Grant
    Filed: January 14, 2002
    Date of Patent: April 6, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventor: Yasuyuki Miyaoka
  • Patent number: 6716488
    Abstract: A ferrite layer formation process that may be performed at a lower temperature than conventional ferrite formation processes. The formation process may produce highly anisotropic structures. A ferrite layer is deposited on a substrate while the substrate is exposed to a magnetic field. An intermediate layer may be positioned between the substrate and the ferrite to promote bonding of the ferrite to the substrate. The process may be performed at temperatures less than 300° C. Ferrite film anisotropy may be achieved by embodiments of the invention in the range of about 1000 dyn-cm/cm3 to about 2×106 dyn-cm/cm3.
    Type: Grant
    Filed: June 22, 2001
    Date of Patent: April 6, 2004
    Assignee: Agere Systems Inc.
    Inventors: Debra Anne Fleming, Gideon S. Grader, David Wilfred Johnson, Jr., John Thomson, Jr., Robert Bruce Van Dover
  • Patent number: 6579635
    Abstract: A ferromagnetic film suitable for ultra-high density perpendicular recording, and a process for producing the film. The process generally entails forming a film of ferromagnetic material on a surface of a substrate, such that the film is characterized by perpendicular magnetic anisotropy and comprises a plurality of magnetic domains defined by domain walls perpendicular to a major surface of the film. The ferromagnetic film is formed to have a linear strain defect for the purpose of smoothing and stabilizing the domain walls during subsequent magnetization reversal of the ferromagnetic material. Such smoothing and stabilizing serves to control temporal magnetic noise due to motion of magnetic domains, arrest domain wall motion (reducing velocity) when the film is subjected to the magnetic reversal fields, and controls spatial magnetic noise due to domain wall jaggedness.
    Type: Grant
    Filed: July 26, 2001
    Date of Patent: June 17, 2003
    Assignee: International Business Machines Corporation
    Inventors: Lia Krusin-Elbaum, Takasada Shibauchi
  • Publication number: 20030107832
    Abstract: The invention relates to a marking device (1, 11) for the identification of objects with a coding of regions (4, 5, 13) with different magnetic properties. The marking device is characterized in that magnetic regions (4, 5, 13) are so magnetically biased that their hysteresis loops (7, 8, 15) are shifted on the field strength axis (H) relative to the magnetization axis (M).
    Type: Application
    Filed: September 26, 2002
    Publication date: June 12, 2003
    Inventors: Jan Morenzin, Daniel Schondelmaier, Wolfgang Eberhardt
  • Patent number: 6495275
    Abstract: A magnetoresistance effect element includes a free layer, a pinned layer and a non-magnetic intermediate layer interposed between the free layer and the pinned layer. Additionally, a metal barrier layer is provided adjacent to the first magnetic layer. An electron reflecting layer located adjacent to the metal barrier layer contains at least one selected from oxides, nitrides, carbides, fluorides, chlorides, sulfides and borides.
    Type: Grant
    Filed: August 13, 2001
    Date of Patent: December 17, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuzo Kamiguchi, Akiko Saito, Katsuhiko Koui, Masatoshi Yoshikawa, Hiromi Yuasa, Hideaki Fukuzawa, Susumu Hashimoto, Hitoshi Iwasaki, Hiroaki Yoda, Masashi Sahashi
  • Patent number: 6465053
    Abstract: Magnetic field sensors and magnetic memories have at least two magnetoresistive bridge elements (A,B,C,D), wherein each magnetoresistive element comprises a free (F) and a pinned (P) ferromagnetic layer. The magnetization directions of pinned ferromagnetic layers are different for the two bridge elements. In the method, in a first deposition step, a first ferromagnetic layer of one of the two said elements is deposited, during which deposition a magnetic field is applied to pin the magnetization direction MP in the first ferromagnetic layer in a first direction. Then, in a second deposition step, a second ferromagnetic layer of the other of the two said elements is deposited, during which deposition a magnetic field is applied to pin the magnetization direction in the second ferromagnetic layer in a second direction different from, preferably opposite to, the magnetization direction in the first ferromagnetic layer.
    Type: Grant
    Filed: February 16, 2001
    Date of Patent: October 15, 2002
    Inventors: Kars-Michiel Hubert Lenssen, Antonius Emilius Theodorus Kuiper, Joannes Baptist Adrianus Dionisius Van Zon
  • Patent number: 6403169
    Abstract: One aspect of the present invention provides a method of producing a security document, including the steps of: (a) forming a sheet-like substrate of plastics material having first and second opposing surfaces, (b) coating a first layer of polymer material containing magnetic particles on the first opposing surface, (c) melting at least a portion of the first layer such that the magnetic particles can orient under the influence of a magnetic field, (d) applying the magnetic field so as to form a magnetic watermark, and (e) allowing the first layer portion to cool so as to fix the orientation of the magnetic particles
    Type: Grant
    Filed: March 13, 2000
    Date of Patent: June 11, 2002
    Assignee: Securency Pty Ltd.
    Inventors: Bruce Alfred Hardwick, Gary Power
  • Patent number: 6391393
    Abstract: A method of forming a dual-level memory material using field structured materials. The field structured materials are formed from a dispersion of ferromagnetic particles in a polymerizable liquid medium, such as a urethane acrylate-based photopolymer, which are applied as a film to a support and then exposed in selected portions of the film to an applied magnetic or electric field. The field can be applied either uniaxially or biaxially at field strengths up to 150 G or higher to form the field structured materials. After polymerizing the field-structure materials, a magnetic field can be applied to selected portions of the polymerized field-structured material to yield a dual-level memory material on the support, wherein the dual-level memory material supports read-and-write binary data memory and write once, read many memory.
    Type: Grant
    Filed: February 22, 2001
    Date of Patent: May 21, 2002
    Assignee: Sandia Corporation
    Inventors: James E. Martin, Robert A. Anderson, Chris P. Tigges
  • Patent number: 6372302
    Abstract: The present invention provides a magnetic recording medium having a thinned magnetic layer, excellent electromagnetic conversion characteristics and an excellent durability, and a process for producing the same. A magnetic recording medium comprising a lower non-magnetic layer containing at least a carbon black and a radiation curing type binder resin on a non-magnetic support and an upper magnetic layer having a thickness of 0.30 &mgr;m or less on the lower non-magnetic layer, wherein the upper magnetic layer contains at least a ferromagnetic powder, a binder resin and an abrasive having a Mohs hardness of 6 or higher and a smaller average particle size than the thickness of the upper magnetic layer. The thickness of the upper magnetic layer is, for example, 0.05 to 0.30 &mgr;m. The average particle size of the abrasive is, for example, 0.01 to 0.2 &mgr;m.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: April 16, 2002
    Assignee: TDK Corporation
    Inventors: Shigeo Kurose, Akihiko Seki, Katsuhiko Yamazaki
  • Patent number: 6319544
    Abstract: A method of manufacturing a MR sensor having at least an anti-ferromagnetic layer and a ferromagnetic layer, and to a method for manufacturing a magnetic head with the MR sensor. The sensor utilizes bias magnetic field provided by exchange coupling between the anti-ferromagnetic layer and the ferromagnetic layer. The sensor manufacturing method includes a step of depositing an anti-ferromagnetic layer to have a larger thickness than a target thickness, a step of ordering the deposited anti-ferromagnetic layer, and a step of thinning the ordered anti-ferromagnetic layer to have the target thickness.
    Type: Grant
    Filed: December 28, 1999
    Date of Patent: November 20, 2001
    Assignee: TDK Corporation
    Inventors: Tetsuro Sasaki, Hiroaki Kawashima
  • Patent number: 6235368
    Abstract: A magnetic recording medium which consists of at least two layers cast one on top of the other is described, the lower layer containing acicular magnetic pigments having a field strength of 5-40 kA/m and a magnetization of 20-70 nTm3/g and the upper layer containing a high-density metal powder dispersion. After application of the layers, the magnetic recording medium is subjected to a magnetic disorientation treatment while the layers are in the wet state, so that said recording medium has virtually no magnetic and mechanical anisotropy. The magnetic recording medium produced in this manner is particularly suitable for floppy disks having a high storage capacity of substantially more than 100 megabytes.
    Type: Grant
    Filed: September 21, 1998
    Date of Patent: May 22, 2001
    Assignee: EMTEC Magnetics GmbH
    Inventors: Hans-Bertram Wiegemann, Peter Stehle, Hansjörg Traub, Helmut Jakusch
  • Patent number: 6129957
    Abstract: A method of manufacturing a magnetoresistive head comprises forming a magnetoresistive structure with a magnetoresistive element with a first AFM element. Perform a first annealing step at a high temperature with a high magnetic field. Form the remaining MR structure including second AFM elements. Perform a low magnetic field (H.sub.ann) annealing step following the fabrication of the second AFM elements. Then perform a no externally applied field (H.sub.ann =0) annealing step at a high temperature to increase the H.sub.ex of the second AFM element to full strength, whereby the stability of the first AFM element is enhanced or increases its H.sub.ex if there were a decrease during the low magnetic field annealing step.
    Type: Grant
    Filed: October 12, 1999
    Date of Patent: October 10, 2000
    Assignee: Headway Technologies, Inc.
    Inventors: Rongfu Xiao, Chyu-Jiuh Torng, Tai Min, Hui-Chuan Wang, Cherng-Chyi Han, Mao-Min Chen, Po-Kang Wan
  • Patent number: 6120916
    Abstract: A composite magnetic material showing reduced losses and reduced permeability when it is subjected to a magnetic field at frequencies below approximately 100 MHz. It comprises magnetic particles in the form of wafers dispersed in a dielectric binder. The polycrystalline magnetic ceramic wafers are oriented so that their main faces are substantially parallel to the magnetic field.Application especially to cores of inductors or transformers.
    Type: Grant
    Filed: September 9, 1996
    Date of Patent: September 19, 2000
    Assignee: Thomson-CSF
    Inventors: Jean-Pierre Delvinquier, Richard Lebourgeois, Michel Pate, Claude Rohart
  • Patent number: 6110539
    Abstract: A method for creating a magnetically permeable film on a substrate surface by deposition of successive layers of a magnetic material, during deposition of each layer a magnetic field being provided near said surface having a field direction substantially parallel to the surface. In order to tune the permeability of the magnetic material the method builds up the magnetically permeable film by forming each layer by depositing a ferromagnetic material to a thickness maximally corresponding to substantially ##EQU1## where L.sub.ex is equal to ##EQU2## with A being the exchange constant of the ferromagnetic material and K.sub.u being the uniaxial anisotropy constant, and changing the magnetic field direction during formation of said layer by an angle other than substantially 180.degree..
    Type: Grant
    Filed: January 27, 1999
    Date of Patent: August 29, 2000
    Assignee: U.S. Philips Corporation
    Inventors: Pascal J.H. Bloemen, Jacobus J.M. Ruigrok