Magnetic Feature Patents (Class 428/900)
-
Patent number: 6764721Abstract: 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: GrantFiled: October 20, 2003Date of Patent: July 20, 2004Assignee: Fuji Electric Co., Ltd.Inventors: Hiroyuki Uwazumi, Yasushi Sakai, Toyoji Ataka
-
Patent number: 6761982Abstract: A magnetic recording medium containing a non-magnetic substrate, an orientation-determining layer for causing the non-magnetic undercoat layer assume to have a predominant orientation plane of (200), a non-magnetic undercoat layer, a magnetic layer, and a protective layer, in order, is disclosed. The non-magnetic undercoat layer 3 has a bcc structure; the orientation-determining layer has a crystal structure in which columnar fine crystal grains are inclined in a radial direction; and the ratio of a coercive force in a circumferential direction of the magnetic layer (Hcc) to a coercive force in a radial direction of the magnetic layer 4 (Hcr)is more than 1. The magnetic layer includes a plurality of magnetic films and having an hcp structure and a predominant orientation plane of (110), and permits antiferromagnetic bonding to be formed therebetween.Type: GrantFiled: December 28, 2001Date of Patent: July 13, 2004Assignee: Showa Denko Kabushiki KaishaInventors: Akira Sakawaki, Hiroshi Sakai
-
Patent number: 6761983Abstract: The magnetic information recording medium includes a backing layer containing Fe and C as its main ingredients, having a substantially amorphous structure, and having an easy axis of magnetization in an in-plane direction, and a magnetic layer having an easy axis of magnetization in a vertical direction and recording information.Type: GrantFiled: June 4, 2002Date of Patent: July 13, 2004Assignee: Fujitsu LimitedInventor: Takeshi Morikawa
-
Patent number: 6759149Abstract: Laminated magnetic recording medium with two Co-containing layers separated by a non-magnetic interlayer is stablished by Ru-containing layers between the recording layers and Co-containing stablization layers through antiferromagnetic coupling.Type: GrantFiled: July 18, 2001Date of Patent: July 6, 2004Assignee: Seagate Technology LLCInventors: Qixu Chen, Zhong Wu, Rajiv Y. Ranjan
-
Patent number: 6756113Abstract: A magnetic recording medium includes a first underlying film of a NiTa alloy having a nonmagnetic amorphous structure and formed on a nonmagnetic substrate, and a second underlying film made of an alloy containing Cr and Ti, further a first magnetic film of a CoCrPt alloy, a nonmagnetic intermediate film of Ru and a second magnetic film of a CoCrPtB alloy that are serially formed over the first underlying film, wherein oxygen locally exists in an interface between the first underlying film and the second underlying film.Type: GrantFiled: February 20, 2002Date of Patent: June 29, 2004Assignee: Hitachi Storage Technologies Japan, Ltd.Inventors: Yoshibumi Matsuda, Koji Sakamoto, Tetsuya Kanbe, Yotsuo Yahisa
-
Patent number: 6756135Abstract: A spin valve thin-film magnetic element has an improved rate of change in resistance (&Dgr;R/R) that can be used for a narrower magnetic track. The spin valve thin-film magnetic element has a laminate that include an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic conductive layer, a free magnetic layer, a back layer, specular-reflection layers and a pair of electrode layers formed at the two sides of the laminate. Preferably the specular reflection layer includes an oxide, such as &agr;-Fe2O3 or NiO, or a half-metal Heusler alloy, such as NiMnSb or PtMnSb.Type: GrantFiled: June 12, 2001Date of Patent: June 29, 2004Assignee: Alps Electric Co., Ltd.Inventors: Naoya Hasegawa, Kenji Honda, Yoshihiko Kakihara
-
Patent number: 6753078Abstract: A magnetic recording medium includes a highly permeable magnetic layer proximal to a recording layer. During recording, the permeable magnetic layer modifies the recording field from a recording head to produce consistently shaped recording transitions with a significant perpendicular component. The transitions are consistently shaped even though the distance between the recording head and the surface of the medium may change. Transitions so formed result in a reduction of noise from the medium surface roughness. The permeable magnetic layer further reduces noise caused by stray dipole fields.Type: GrantFiled: October 30, 2001Date of Patent: June 22, 2004Assignee: Imation Corp.Inventors: Alexander Roesler, Yung Yip
-
Patent number: 6753100Abstract: The coercivity of a magnetic recording medium such as a magnetic disk is determined by providing at least two magnetic layers in the recording medium with the relative thicknesses of the two magnetic layers determining coercivity without the need for changing substrate temperature, underlayer thickness or substrate biasing during manufacture. Each magnetic layer is a cobalt alloy of different composition and intrinsic magnetic properties. Importantly, the coercivity can be modified without adversely affecting remanence or squareness of the hysteresis transition region for the recording medium.Type: GrantFiled: May 30, 2000Date of Patent: June 22, 2004Assignee: Maxtor CorporationInventors: Bunsen Y. Wong, Bing Zhang, Kenneth E. Johnson
-
Patent number: 6753103Abstract: A disk for a hard disk drive. The disk includes a first layer of magnetic material located over a substrate, an intermediate layer located over the first magnetic layer and a second layer of magnetic material located over the intermediate layer. The second layer may include cobalt and chromium. The intermediate layer may include titanium. The first magnetic layer include iron, hafnium and nitrogen (FeHfN). This composition of the first magnetic layer shows higher saturation magnetization and lower roughness, and increases the nucleation field of the disk.Type: GrantFiled: October 4, 2002Date of Patent: June 22, 2004Assignee: Samsung Electronics Co. Ltd.Inventors: Sooyoul Hong, Daehoon Hong, Taekdong Lee, Hyung J. Lee
-
Patent number: 6753084Abstract: Spindle-shaped magnetic alloy particles containing Fe and Co as main components of the present invention have a cobalt content of 20 to 50 atm % (calculated as Co) based on whole Fe; an average major axis diameter (L) of 0.03 to 0.10 &mgr;m; a coercive force value of 159.2 to 238.7 kA/m (2,000 to 3,000 Oe); a crystallite size of 100 to 160 Å; and an activation volume (Vact) of 0.01 to 0.07E-4 &mgr;m3. A high-density magnetic recording medium produced by using such spindle-shaped magnetic alloy particles containing Fe and Co as main components, have an excellent output characteristics in a short wavelength region, a considerably reduced noise and an excellent storage stability.Type: GrantFiled: December 20, 2001Date of Patent: June 22, 2004Assignee: Toda Kogyo CorporationInventors: Masaaki Maekawa, Haruki Kurokawa, Kenji Okinaka, Akinori Yamamoto, Yasutaka Ota
-
Patent number: 6753101Abstract: A magnetic recording medium is provided with at least one exchange layer structure, and a magnetic layer formed on the exchange layer structure. The exchange layer structure includes a ferromagnetic layer and a non-magnetic coupling layer provided on the ferromagnetic layer and under the magnetic layer.Type: GrantFiled: June 6, 2000Date of Patent: June 22, 2004Assignee: Fujitsu LimitedInventors: E. Noel Abarra, Iwao Okamoto, Yoshifumi Mizoshita, Yuki Yoshida
-
Publication number: 20040115425Abstract: The present invention relates to an information carrier which, by means of magnetism, can be applied to a suitable substrate. This information carrier consists for an important part of plastic, while at least one layer of that plastic comprises metal particles dispersed therein.Type: ApplicationFiled: January 16, 2004Publication date: June 17, 2004Inventor: Peter Maria Kroonbergs
-
Patent number: 6749750Abstract: A magnetic sheet assembly for application to a device adapted for magnetic separation, the magnetic sheet assembly comprising: a magnetic sheet; a permanent, pressure sensitive adhesive; a carrier sheet; and a non-permanent pressure sensitive adhesive. Also provided is a method of mounting and removably adhering the magnetic sheet assembly to a surface of a device for magnetic separation, the method comprising the steps of aligning the magnetic sheet assembly with the surface of the device; and pressing the aligned magnetic sheet assembly in placing its non-permanent adhesive face into adhesive contact with the surface of the device.Type: GrantFiled: October 11, 2001Date of Patent: June 15, 2004Assignee: Biocrystal Ltd.Inventors: Emilio Barbera-Guillem, Marlin O. Thurston
-
Patent number: 6749955Abstract: An ultra-high density information recording media has 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: GrantFiled: January 23, 2003Date of Patent: June 15, 2004Assignees: 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: 6746786Abstract: A magnetic recording medium, comprises a substrate; and a Co-containing spinel-type iron oxide thin film formed on the substrate, having a Co content of 1 to 20 mol % based on Fe, a coercive force value of not less than 159 kA/m (2,000 Oe), a thickness of 5 to 200 nm, a center line average height Ra of 0.1 to 0.8 nm and a maximum height (Rmax) of not more than 10 nm. The magnetic recording medium is capable of exhibiting a relatively high coercive force, especially a coercive force of not less than 159 kA/m (2,000 Oe) despite as small a film thickness as not more than 200 nm, and an excellent surface smoothness.Type: GrantFiled: October 15, 2001Date of Patent: June 8, 2004Assignee: Toda Kogyo CorporationInventors: Teruaki Santoki, Yasuo Kakihara, Mitsuru Matsuura, Setsuo Yamamoto
-
Patent number: 6746767Abstract: 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: GrantFiled: August 16, 2002Date of Patent: June 8, 2004Assignee: Degussa AGInventors: Heiko Gottfried, Christian Janzen, Markus Pridoehl, Paul Roth, Berthold Trageser, Guido Zimmermann
-
Patent number: 6743528Abstract: A magnetic recording medium comprising a non-ferromagnetic substrate and a magnetic recording film formed on the substrate with an underlayer interposed therebetween, wherein the magnetic recording film comprises a plurality of magnetic layers and an interlayer made of a material having a B2 crystal structure or an interlayer made of Ru, disposed between the adjacent magnetic layers.Type: GrantFiled: June 29, 2001Date of Patent: June 1, 2004Assignee: Komag, Inc.Inventors: Michinobu Suekane, Makoto Imakawa, Takehiko Hiruma
-
Patent number: 6743503Abstract: Improved multilayer magnetic superlattice structures, such as (Co/Pt)n and (Co/Pd)n, having predetermined, very high perpendicular magnetic coercivities are formed by sputter deposition of predetermined thickness, ultra-thin seed layers on the substrate prior to formation thereon of the superlattice structure by sputtering at at least a predetermined minimum sputtering gas pressure. The multilayer magnetic superlattice structures are advantageously utilized in the formation of thermally stable, perpendicular magnetic recording (MR) media having very high areal recording densities.Type: GrantFiled: August 29, 2000Date of Patent: June 1, 2004Assignee: Seagate Technology LLCInventor: Ga-Lane Chen
-
Patent number: 6743529Abstract: A process for producing a glass substrate for a magnetic recording medium by forming a surface roughness in a main surface of a glass plate that has been formed into a disk shape, includes: imparting a processing mark having a permanent strain to the main surface of the glass plate in a circumferential direction thereof; and chemically etching the whole main surface of the glass plate, so as to form the surface roughness.Type: GrantFiled: December 17, 2001Date of Patent: June 1, 2004Assignee: Nippon Sheet Glass Co., Ltd.Inventors: Yasuhiro Saito, Hiroshi Ikeda, Junji Kurachi, Kazuishi Mitani
-
Patent number: 6737158Abstract: Composites comprising porous polymeric membrane films meeting the following equation: 75 MPa<(longitudinal membrane tensile modulus+transverse membrane tensile modulus)/2, wherein at least a portion of the porosity of the membrane is imbibed with resin and methods for making the same. The composites have unusually high resistance to fracture and catastrophic failure.Type: GrantFiled: October 30, 2002Date of Patent: May 18, 2004Assignee: Gore Enterprise Holdings, Inc.Inventor: Samuel A. Thompson
-
Patent number: 6735057Abstract: A method of magnetic recording/reproducing is disclosed, which comprises reproducing with a magnetoresistive head (MR head) signals recorded in a magnetic recording medium comprising a support having thereon a magnetic layer comprising mainly ferromagnetic particles and a binder, wherein the MR head has an element thickness of 50 nm or smaller and the ferromagnetic particles are hexagonal-ferrite magnetic particles having an average tabular diameter of from 10 to 40 nm and an average tabular thickness smaller than the element thickness of the MR head used for reproduction.Type: GrantFiled: June 19, 2002Date of Patent: May 11, 2004Assignee: Fuji Photo Film Co., Ltd.Inventor: Kiyomi Ejiri
-
Patent number: 6733906Abstract: A method is provided for coating one or more fluid layers on a substrate to form magnetic recording media such as magnetic tape and diskettes. The method takes advantage of fluid coating formulations having a particular rheology that enables the coating of one or more magnetic layers with reduced thicknesses while achieving increased coating speeds. With proper rheology, one or more layers can be coated on a substrate traveling at increased speeds while maintaining desired coating thicknesses.Type: GrantFiled: July 27, 2001Date of Patent: May 11, 2004Assignee: Imation Corp.Inventors: William Blake Kolb, Gary L. Huelsman
-
Publication number: 20040084304Abstract: Composites comprising porous polymeric membrane films meeting the following equation: 75 MPa<(longitudinal membrane tensile modulus+transverse membrane tensile modulus)/2, wherein at least a portion of the porosity of the membrane is imbibed with resin and methods for making the same. The composites have unusually high resistance to fracture and catastrophic failure.Type: ApplicationFiled: October 30, 2002Publication date: May 6, 2004Inventor: Samuel A. Thompson
-
Patent number: 6730421Abstract: A magnetic recording medium (300) includes a substrate (1) and on the substrate (1) a first underlying layer (32), a second underlying layer (33), a magnetic layer (34), and a protective layer (35). Because of the existence of the first underlying layer (32) of Hf, initial growth layer having no specific crystal structure is prevented from growing in the second underlying layer (33). The second underlying layer (33) has a structure in which CoO particles having a cross section of a regular hexagon and separated by SiO2 portion are arranged in honeycomb. Since magnetic particles are epitaxially grown from CoO particles, the size of the magnetic particles and particle size distribution can be controlled, and the magnetic interaction between magnetic particles can be lessened. The underlying layer (33) and the protective layer (35) are formed by ECR sputtering. Such a magnetic recording medium is free from noise and thermal fluctuation, and ultrahigh recording density over 40 Gbit/inch2 is realized.Type: GrantFiled: November 9, 2001Date of Patent: May 4, 2004Assignee: Hitachi, Maxell, Ltd.Inventors: Fumiyoshi Kirino, Nobuyuki Inaba, Teruaki Takeuchi, Kouichirou Wakabayashi
-
Patent number: 6730420Abstract: A magnetic medium having at least two intermediate layers between an underlayer and a magnetic layer. The first intermediate layer is designed to provide a good lattice match to the underlayer, while the second intermediate layer is designed to provide a good lattice match to the magnetic layer. Typically, the underlayer has one structure, such as body centered cube, while the magnetic layer has a second structure such as hexagonal close pack. In preferred embodiments, the transition from the one structure to the other structure occurs in the intermediate layers. For example, the first intermediate layer may be a hexagonal close pack structure. Because of the mismatch between the underlayer and the first layer, there may be crystal defects in this first intermediate layer. However, any remaining stress and mismatch is absorbed through the second layer, so that the second layer presents a substantially defect-free surface on which the magnetic layer may grow.Type: GrantFiled: October 31, 2000Date of Patent: May 4, 2004Assignee: Komag, Inc.Inventors: Gerardo Bertero, Tu Chen, Charles Chen, Wei Cao
-
Publication number: 20040081841Abstract: A magnetic memory device includes a first wiring which runs in the first direction, a first metal layer which is arranged above the first wiring, a first magneto resistive effect element which is arranged in a predetermined region on the first metal layer, a first contact layer which is arranged on the first magneto resistive effect element, a second wiring which runs in the second direction different from the first direction, is arranged on the first contact layer, and has a projection that covers the top of the first contact layer, and a first insulating film which is buried around the first metal layer, first magneto resistive effect element, first contact layer, and second wiring, and has a surface flush with that of the second wiring.Type: ApplicationFiled: November 26, 2002Publication date: April 29, 2004Inventor: Kentaro Nakajima
-
Patent number: 6727010Abstract: A magnetic recording medium comprising, in order, a non-metallic substrate; an amorphous metallic film having an amorphous structure; a crystal-structure-regulating film of NiP-based alloy; and a non-magnetic undercoat film and a magnetic film; and wherein the crystal-structure-regulating film has a film thickness of 50 nm or less, and a total film thickness of the amorphous metallic film and the crystal-structure-regulating film is at least 60 nm is disclosed.Type: GrantFiled: December 27, 2001Date of Patent: April 27, 2004Assignee: Showa Denko Kabushiki KaishaInventors: Kenzo Hanawa, Hiroshi Ohsawa
-
Patent number: 6723914Abstract: There is provided a composite magnetic tape which can be easily applied irrespective of the inside or outside of an electronic equipment, prevent radiation of undesired electromagnetic waves from the inside of the equipment and reflection into the inside of the equipment, and shield electromagnetic noise from the outside of the equipment. The tape may be in the form of an adhesive tape or a self-welding tape. The tape is constituted of a composite magnetic layer formed by dispersing soft magnetic powder into an organic binding agent. Alternatively, it may have a stacked structure of a composite magnetic layer and a conductor layer.Type: GrantFiled: February 23, 2000Date of Patent: April 20, 2004Assignee: NEC Tokin CorpInventors: Koji Kamei, Norihiko Ono, Mitsuharu Sato
-
Patent number: 6723457Abstract: Provided are a double-layer perpendicular magnetic recording medium having a high medium S/N at an areal recording density of 50 Gbits or more per square inch, and a magnetic storage apparatus having excellent reliability with a low error rate. The perpendicular magnetic recording medium is formed by sequentially laminating a domain control layer, an amorphous soft magnetic underlayer, an intermediate layer, and a perpendicular recording layer on a substrate. The domain control layer is a triple-layer film formed by laminating a first polycrystalline soft magnetic layer, a disordered antiferromagnetic layer, and a second polycrystalline soft magnetic layer from a substrate side.Type: GrantFiled: February 19, 2002Date of Patent: April 20, 2004Assignee: Hitachi, Ltd.Inventors: Kiwamu Tanahashi, Atsushi Kikugawa, Noboru Shimizu, Yukio Honda, Yuzuru Hosoe
-
Patent number: 6723415Abstract: A magnetic recording medium having a non-magnetic support, at least one primer layer on one surface of the support, a magnetic layer on the primer layer and a back coat layer on the other surface of the non-magnetic support, in which the support has a thickness of 2 to 5 &mgr;m, the surface roughness (Ra) of the support on its surface carrying the primer layer and the magnetic layer is from 2.5 nm to 20 nm, the thickness of the primer layer is 1.5 &mgr;m or less, and the primer layer contains 2 to 30 % by weight, based on the weight of all inorganic powder in the primer layer, of alumina powder having a particle size of 0.01 &mgr;m to 0.1 &mgr;m.Type: GrantFiled: December 28, 2000Date of Patent: April 20, 2004Assignee: Hitachi Maxell, Ltd,Inventors: Muneyoshi Ochi, Takeki Mochizuki, Koh Tsukamoto
-
Patent number: 6723458Abstract: A magnetic recording medium that is capable of recording and reading back information at a higher density by improving the read/write characteristics and thermal stability, a method of manufacture therefor, and a magnetic read/write apparatus are provided. This magnetic recording medium, comprises an orientation control film that controls the orientation of a film provided directly thereabove, a perpendicular magnetic film, of which the axis of easy magnetization is generally oriented perpendicular to a non-magnetic substrate, and a protective film, that are provided on the non-magnetic substrate, wherein the perpendicular magnetic film is made of a material which contains Co, Cr, Pt and Cu, the Cr content being 16 at % to 24 at % and the Cu content being 0.Type: GrantFiled: August 15, 2002Date of Patent: April 20, 2004Assignees: Showa Denko K.K., Toshiba CorporationInventors: Kenji Shimizu, Akira Sakawaki, Hui Yang, Hiro Mochizuki, Hiroshi Sakai, Takashi Hikosaka, Futoshi Nakamura
-
Patent number: 6720074Abstract: A series of bulk-size magnetic/insulating nanostructured composite soft magnetic materials with significantly reduced core loss and its manufacturing technology. This insulator coated magnetic nanostructured composite is comprises a magnetic constituent, which contains one or more magnetic components, and an insulating constituent. The magnetic constituent is nanometer scale particles (1-100 nm) coated by a thin-layered insulating phase (continuous phase). While the intergrain interaction between the immediate neighboring magnetic nanoparticles separated by the insulating phase (or coupled nanoparticles) provide the desired soft magnetic properties, the insulating material provides the much demanded high resistivity which significantly reduces the eddy current loss. The resulting material is a high performance magnetic nanostructured composite with reduced core loss.Type: GrantFiled: October 26, 2001Date of Patent: April 13, 2004Assignee: Inframat CorporationInventors: Yide Zhang, Shihe Wang, Danny Xiao
-
Patent number: 6716489Abstract: 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: GrantFiled: January 14, 2002Date of Patent: April 6, 2004Assignee: Canon Kabushiki KaishaInventor: Yasuyuki Miyaoka
-
Patent number: 6716543Abstract: The present invention provides a magnetic recording medium including at least a nonmagnetic undercoat layer, a nonmagnetic metallic intermediate layer, a magnetic layer, a protective film, and a liquid lubricant layer sequentially laminated on a nonmagnetic substrate, wherein the magnetic layer contains crystal grains having ferromagnetism and nonmagnetic grain boundaries surrounding the crystal grains, and the nonmagnetic metallic intermediate layer contains at least one layer, and the crystal structure of each layer being a hexagonal close-packed structure; and a method for producing the magnetic recording medium. The magnetic recording medium shows high coercive force Hc and a low medium noise, and its manufacturing cost is also low.Type: GrantFiled: February 22, 2001Date of Patent: April 6, 2004Assignee: Fuji Electric Co., Ltd.Inventors: Hiroyuki Uwazumi, Tadaaki Oikawa, Naoki Takizawa
-
Patent number: 6716516Abstract: 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: GrantFiled: July 26, 2002Date of Patent: April 6, 2004Assignee: Hitachi, Ltd.Inventors: Masaaki Futamoto, Nobuyuki Inaba, Yoshiyuki Hirayama, Yukio Honda, Kazuetsu Yoshida, Kenya Ito
-
Patent number: 6713196Abstract: The present invention provides a high-density, low-noise magnetic recording medium. This magnetic recording medium includes a substrate, a non-magnetic underlayer formed on the substrate, and a magnetic recording layer formed on the underlayer. The magnetic recording layer contains cobalt as the main component, 10 atm % to 18 atm % of chromium, 5 atm % to 20 atm % of platinum, and 10 atm % to 20 atm % of boron.Type: GrantFiled: November 27, 2000Date of Patent: March 30, 2004Assignee: Fujitsu LimitedInventor: Isatake Kaitsu
-
Patent number: 6713197Abstract: A soft magnetic laminate layer is arranged between a nonmagnetic substrate and a perpendicular magnetic recording layer so as to provide a perpendicular magnetic recording medium low in noise and capable of a high density recording. The soft magnetic laminate layer comprises a soft magnetic layer having a thickness not larger than 500 Å and a nonmagnetic layer, comprises a first soft magnetic layer and a second soft magnetic layer differing from the first soft magnetic layer in the crystal structure, or comprises a layer of a granular structure consisting of magnetic particles and a nonmagnetic matrix and a soft magnetic layer.Type: GrantFiled: March 15, 2001Date of Patent: March 30, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Futoshi Nakamura, Takashi Hikosaka, Soichi Oikawa, Hideo Ogiwara
-
Patent number: 6713155Abstract: A base film for magnetic recording media, comprising a film layer containing inert fine particles and having an agglomeration rate of the inert fine particles on the surface of the film of 4 to 20%, or a film layer containing inert fine particles and an ester wax of an aliphatic monocarboxylic acid having 8 or more carbon atoms and a polyhydric alcohol and having a water contact angle of the exposed surface of 70 to 90°. A magnetic recording medium, particularly a metal deposited thin film magnetic recording medium comprising this base film is excellent in electromagnetic conversion characteristics.Type: GrantFiled: December 21, 2001Date of Patent: March 30, 2004Assignee: Teijin LimitedInventors: Makoto Handa, Hirofumi Murooka, Toshifumi Osawa
-
Patent number: 6709016Abstract: The present invention is directed to a method and a device for the production of security elements for electronic article surveillance, the security elements being comprised of at least two layers, as well as to a web material manufactured by means of the method the present invention proposes a simple, economical method, a corresponding device for the production of web material, as well as to a web material manufactured by the method for the purpose of electronic article surveillance. With regard to the method of the present invention, it is accomplished in that sections of a predetermined length cut from a second material web are conveyed in a direction transverse to the running direction of a first continuous material web and are applied to the first material web.Type: GrantFiled: July 15, 2002Date of Patent: March 23, 2004Inventors: Detlef Duschek, Gordon Klassen
-
Patent number: 6709774Abstract: A method of influencing variations in composition of thin films is described. The elemental plasma field distribution in sputtering systems is manipulated by generating a nonuniform electric field along a surface of the substrate to alter the composition by differentially re-sputtering the target elements. The nonuniform electric field is applied by one or more electrodes in contact with a conductive surface or by using an RF bias signal. The nonuniform electric field is used to modulate the kinetic energy of the ions generated in the plasma which strike the thin film's surface. Since the kinetic energy and the mass of the sputtering gas ions and neutrals affect the re-sputtering rate, the nonuniform electric field differentially affects the elements being deposited according to mass. By applying varying electric potentials at a plurality of points on a conductive surface of a substrate, the electric field across the surface of the substrate can be modulated in a variety of patterns.Type: GrantFiled: September 18, 2001Date of Patent: March 23, 2004Assignee: International Business Machines CorporationInventors: Ernesto E. Marinero, Timothy Martin Reith, Hal Jerves Rosen, Brian R. York
-
Patent number: 6709775Abstract: A magnetic recording medium capable of suppressing the effects of thermal agitation and simultaneously reducing the average grain diameter and the standard deviation of magnetic crystal grains constituting a ferromagnetic metal film, without changing the film thickness of a metal under-layer or the film thickness of a ferromagnetic metal layer forming a recording layer, as well as a production method thereof, and a magnetic recording device. The magnetic recording medium includes a ferromagnetic metal layer of a cobalt based alloy formed on a base material with a metal underlayer having chromium as a major constituent disposed there between, wherein a seed layer having at least tungsten is provided between the base material and the metal under-layer, and the seed layer is an islands type film.Type: GrantFiled: November 28, 2001Date of Patent: March 23, 2004Inventors: Migaku Takahashi, Satoru Yoshimura, David Djayaprawira, Hiroki Shoji
-
Patent number: 6709773Abstract: A perpendicular magnetic recording medium having a substrate, a seedlayer on the substrate and a magnetic underlayer on the seedlayer, the magnetic underlayer having an easy axis of magnetization substantially directed in a radial or transverse direction, and a process for manufacturing the perpendicular magnetic recording medium are disclosed.Type: GrantFiled: June 5, 2001Date of Patent: March 23, 2004Assignee: Seagate Technology, Inc.Inventors: Chung-Hee Chang, Rajiv Y. Ranjan
-
Patent number: 6706427Abstract: There are disclosed an information recording medium substrate having a surface roughness of Rmax 15 nm or less, and an information recording medium, particularly an information recording medium substrate and information recording medium in which for surfaces of the substrate and medium, a bearing area value (offset bearing area value) in a depth of 0.5 to 5 nm (predetermined slice level) from a bearing height (real peak height) corresponding to the bearing area value of 0.2% to 1.0% is 90% or less, and a manufacture method of the substrate and medium.Type: GrantFiled: December 20, 2000Date of Patent: March 16, 2004Assignee: Hoya CorporationInventors: Tomotaka Yokoyama, Hiroshi Tomiyasu, Masatomo Shibui, Nobuyuki Eto
-
Patent number: 6706394Abstract: The subject invention related to methods and apparatuses for the manufacture of magnetizable carrier particles. In addition the subject invention pertains to particles having one or more of a variety of particle configurations and/or functional features. These geometric particle configurations and/or functional features such as delivering or removing a pay load can be tailored to achieve one or more desired missions. The subject invention also pertains to a method and apparatus for the delivery of particles to target materials, in order to accomplish one or more of a variety of missions. In a specific embodiment of the subject invention, acicular and other particles with a lengthwise dimension that are substantially uniform and homogenous in their geometry are manufactured and provided with magnetizations. In this way, predictable mechanical force responsivity can be achieved when these particles are subjected to an external magnetic field gradient.Type: GrantFiled: May 2, 2001Date of Patent: March 16, 2004Inventors: Manfred R. Kuehnle, Adelheid Kuehnle
-
Patent number: 6703148Abstract: A magnetic recording medium includes an underlayer of a nonmagnetic alloy containing chromium and titanium, a magnetic layer of a Co—Cr—Pt—Ta or Co—Cr—Pt—B alloy, and an intermediate layer of a Co—Cr—Pt alloy and being disposed between the underlayer and the magnetic layer, thereby carrying out high-density information recording and reproducing operation.Type: GrantFiled: August 7, 2002Date of Patent: March 9, 2004Assignee: Hitachi, Ltd.Inventors: Yoshibumi Matsuda, Yotsuo Yahisa, Koji Sakamoto, Yuzuru Hosoe, Akira Kato
-
Patent number: 6699602Abstract: An amorphous magnetic recording medium comprising a substrate and an amorphous magnetic layer, where a magnetic domain formation-controlling layer comprising a main phase and 1 to 3 kinds of discrete spherical isolating phases arranged horizontally in lines in the main phase or 1 to 3 kinds of discrete spherical phases vertically stacked one upon another in the main phase is formed on the top side or the bottom side directly or through at least one of other layers to bring the amorphous magnetic layer into a finer magnetic domain structure, can satisfy high density recording.Type: GrantFiled: March 1, 2002Date of Patent: March 2, 2004Assignee: Hitachi Maxell, Ltd.Inventors: Mitsutoshi Honda, Hiroki Yamamoto, Takashi Naito, Tatsumi Hirano, Tetsuo Nakazawa, Fumiyoshi Kirino, Teruaki Takeuchi, Akira Yano, Nobuyuki Inaba, Satoshi Matsunuma
-
Patent number: 6699601Abstract: A magnetic recording medium which has higher S/N and lower manufacturing cost includes a first underlayer including at least one of Co or Cu and P on a non-magnetic substrate, a second underlayer consisting of a non-magnetic material using Cr, and a magnetic layer on the second underlayer.Type: GrantFiled: March 15, 2000Date of Patent: March 2, 2004Assignee: Fujitsu LimitedInventors: Kenji Sato, Yuki Yoshida
-
Patent number: RE38474Abstract: A magnetic layer structure with a layer of cobalt-chromium-platinum-boron composite alloy containing 10% to 20% B in the magnetic layer. The useful magnetic properties of the magnetic layer structure are achieved by the incorporation of a nucleation layer prior to the deposition of the magnetic layer. The resultant magnetic layer structures have coercivity Hc values in between 2,000 and 5,000 Oe, grain sizes between 30 and 200 Angstroms and anisotropic crystallographic orientation with the c-axis of the cobalt-chromium-platinum-boron in the plane of the medium. These magnetic layer structures are suitable for magnetic data storage devices including magnetic disks.Type: GrantFiled: August 27, 2002Date of Patent: March 23, 2004Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: David T. Margulies, Ernesto E. Marinero, Hal J. Rosen, Brian R. York, Kurt A. Rubin
-
Patent number: RE38501Abstract: A method of recording information on and reproducing information from a magnetooptical recording medium which includes first and second magnetic layers. The method includes the step of projecting a light spot onto the medium. When reproducing information, the light spot is projected onto the medium from the side of the magnetic layer. In this method only a high temperature region of the second magnetic layer within a light spot projection portion is changed to a perpendicular magnetization film so that information recorded in the first magnetic layer is transferred to the perpendicular magnetization film of the second magnetic layer. In addition, information which is transferred to the second magnetic layer is detected by using reflected light from the medium which is subjected to the magneto-optic effect from the perpendicular magnetization film of the second magnetic layer.Type: GrantFiled: March 30, 2001Date of Patent: April 20, 2004Assignee: Canon Kabushiki KaishaInventors: Naoki Nishimura, Hiroshi Omata
-
Patent number: RE38544Abstract: A Co-Pt based magnetic alloy which has been doped with a relatively high amount of nitrogen, e.g., or above 1 at. % is obtained having high coercivity, for example in the range of 1400 Oe or above, and an increased signal-to-noise ratio as compared to the same Co-Pt based alloy which has not been doped with nitrogen. The alloy is vacuum deposited, for example, by sputtering, and the nitrogen may be introduced from the sputtering gas or from the sputtering target. Other low-solubility elements providing the grain uniformity and isolation include: B, P, S, C, Si, As, Se and Te.Type: GrantFiled: July 17, 2000Date of Patent: July 6, 2004Assignee: Komag, Inc.Inventors: Tu Chen, Tsutomu Tom Yamashita, Rajiv Yadav Ranjan, John Ko-Chen Chen, Keith Kadokura, Ting Joseph Yuen