Magnetic Field Or Compass (e.g., Hall Effect Type) Patents (Class 338/32R)
  • Patent number: 6154025
    Abstract: A position sensing device (2) has a magnetic field generating device (3) with at least one magnetic pole (4.sub.j) and a sensor device (5) with at least one sensor (6) with an enhanced, specifically a giant magnetoresistive, effect. The magnetic field generating device (3) is arranged with respect to the sensor device (5) in such a way that the direction of a normal (H.sub.1) to the plane of the sensor (6) runs at an angle different from zero with respect to an imaginary reference line (L.sub.1) on which the at least one magnetic pole (4.sub.j) is located, and the magnetic field generating device (3) is to be moved with respect to the sensor device (5) so that the magnetic field (h) of the at least one magnetic pole (4.sub.j) is detected by the sensor (6), causing a sweep through at least part of the sensor characteristic, with the number of sweeps determined by the number of magnetic poles detected.
    Type: Grant
    Filed: August 17, 1998
    Date of Patent: November 28, 2000
    Assignee: Siemens AG
    Inventors: Wolfgang Schelter, Wolfgang Clemens, Ludwig Schmidt, Michael Vieth
  • Patent number: 6150045
    Abstract: The pinned magnetic layer 2 is composed of a track width region 2' and a dead region 2", the track width region 2' being formed at a spaced apart relation to the bias region 5. Accordingly, magnetization of the track width region 2' is not so strongly affected by the bias region 5, thereby magnetization is fixed along the Y-direction at almost entire region of the track width region 2'. Therefore, the track width region 2' and the free magnetic region are in a crossing relation with each other giving a proper asymmetry in the entire region of the track width region 2'.
    Type: Grant
    Filed: September 16, 1998
    Date of Patent: November 21, 2000
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Toshihiro Kuriyama
  • Patent number: 6137395
    Abstract: A magnetoresistor with an ordered double perovskite structure is an oxide crystal which has an ordered double perovskite crystal structure represented by the general formula of A.sub.2 BB'O.sub.6, wherein A stands for Sr atoms, B for Fe atoms and B' for Mo or Re atoms and wherein the Fe atoms and the Mo or Re atoms are alternately arranged and which exhibits negative magnetoresistive characteristics.
    Type: Grant
    Filed: March 26, 1999
    Date of Patent: October 24, 2000
    Assignees: Agency of Industrial Science and Technology, Ministry of International Trade and Industry, Mitsubishi Electric Corporation, Angstrom Technology Partnership
    Inventors: Keiichiro Kobayashi, Yoshinori Tokura, Tsuyoshi Kimura, Yasuhide Tomioka
  • Patent number: 6132892
    Abstract: A soft magnetic alloy film is essentially consisted of a magnetic alloy having a composition expressed by (Fe.sub.1-a-b Co.sub.a Ni.sub.b).sub.100-X R.sub.X (R is at least one kind of element selected from rare earth elements including Y, 0.ltoreq.a<1, 0 .ltoreq.b<1, 0.ltoreq.a+b<1, 0<x.ltoreq.10 at %). A soft magnetic alloy film has a first phase consisting of a crystal phase, and a second phase different in crystal structure from the first phase. The first phase is composed of crystal phase having, for instance, body-centered cubic structure. The second phase is composed of, for instance, amorphous phase containing R element and/or crystal phase having crystal structure other than body-centered cubic structure containing R element. Since the first phase and the second phase are different each other in their crystal structures, grain growth can be suppressed.
    Type: Grant
    Filed: September 16, 1998
    Date of Patent: October 17, 2000
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Hiroaki Yoda, Susumu Hashimoto
  • Patent number: 6133732
    Abstract: A magnetoresistive effect element comprises a base layer, an antiferromagnetic layer extending over the base layer, a pinned magnetic layer extending over the antiferromagnetic layer, a first non-magnetic layer extending over the pinned magnetic layer, and a free magnetic layer extending over the first non-magnetic layer, wherein the pinned magnetic layer includes at least one selected from the group consisting of Co-based materials, Ni-based materials, Fe-based materials and alloys thereof, and wherein the free magnetic layer includes at least one selected from the group consisting of amorphous magnetic materials, iron nitride based materials, Sendust and alloys based on Co, Fe, Ni, NiFe, NiFeCo, FeCo, CoFeB, CoZrMo, CoZrNb, CoZr, CoZrTa, CoHf, CoTa, CoTaHf, CoNbHf, CoHfPd, CoTaZrNb and CoZrMoNi.
    Type: Grant
    Filed: November 20, 1997
    Date of Patent: October 17, 2000
    Assignee: NEC Corporation
    Inventor: Kazuhiko Hayashi
  • Patent number: 6130599
    Abstract: An electrical sensing apparatus includes a conductor having longitudinally extending sections with parallel central axes and a connector section which extends between the longitudinally extending sections. The connector section has a central axis which extends parallel to the central axes of the longitudinally extending sections. A magnetic flux sensor is disposed adjacent to the connector section to detect variations in current conducted through the conductor. The magnetic flux sensor may be at least partially disposed in a slot in the connector section and have a flux sensitive side surface which extends perpendicular to a central axis of the connector section. The magnetic flux sensor may include an electrically insulating material which is at least partially enclosed by the connector section and a Hall effect device which is supported by the electrically insulating material. The electrically insulating material may be disposed in engagement with the connector section.
    Type: Grant
    Filed: August 3, 1999
    Date of Patent: October 10, 2000
    Assignee: Eaton Corporation
    Inventors: Mark Allan Juds, Kurt Von Eckroth, Charles Joseph Tennies, James Edward Hansen, Mark George Solveson, Jerome Kenneth Hastings, Scott Reid
  • Patent number: 6127053
    Abstract: An SV sensor having a reference (pinned) layer formed of a first high uniaxial anisotropy ferromagnetic material, such as Co--Fe, and a keeper layer formed of a second high uniaxial anisotropy ferromagnetic material, such as Ni--Fe--Nb. Lapping induced stress in the Co--Fe layer having high positive magnetostriction generates a stress-induced uniaxial anisotropy field in the reference layer resulting in enhanced reference layer magnetization. This uniaxial anisotropy field is capable by itself of maintaining a substantial transverse reference layer saturation even at elevated temperatures. Lapping induced stress in the Ni--Fe--Nb layer having high positive magnetostriction generates a stress-induced uniaxial anisotropy field in the keeper layer providing more uniform magnetization and therefore better flux cancellation. The high electrical resistivity of the Ni--Fe--Nb keeper layer has the further benefit of reducing sense current shunting by the keeper layer.
    Type: Grant
    Filed: May 27, 1998
    Date of Patent: October 3, 2000
    Assignee: International Business Machines Corporation
    Inventors: Tsann Lin, Daniele Mauri, Joseph Francis Smyth
  • Patent number: 6124711
    Abstract: A magnetic sensor including a first magnetic layer having an axis of easy magnetization in a first direction; a second magnetic layer having an axis of easy magnetization in a second direction different from the first direction; a third magnetic layer positioned between the first magnetic layer and the second magnetic layer, and having a smaller coercive force than the first magnetic layer and the second magnetic layer; a first insulating layer interposed between the first magnetic layer and the third magnetic layer; and a second insulating layer interposed between the second magnetic layer and the third magnetic layer. An external magnetic field is detected by the use of tunnel resistance between the first magnetic layer and the third magnetic layer and tunnel resistance between the second magnetic layer and the third magnetic layer.
    Type: Grant
    Filed: January 17, 1997
    Date of Patent: September 26, 2000
    Assignee: Fujitsu Limited
    Inventors: Atsushi Tanaka, Masashige Sato
  • Patent number: 6120919
    Abstract: Magnetoresistive and spin valve heads have a layered structure. Common to each of the layered structures of these heads is the combination of a soft-magnetic layer of essentially NiFe near a spacer layer of essentially Ta, which is used for insuring (111) crystal orientation of the NiFe layer. An isolate layer is interposed between the spacer layer and the soft-magnetic layer to prevent a diffusion boundary from being created at the interface of these layers which tends to degrade the soft-magnetic property of the NiFe layer, especially when the thickness of the soft-magnetic layer is 10 and nm or less.
    Type: Grant
    Filed: July 14, 1998
    Date of Patent: September 19, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Satoshi Shigematsu, Takao Imagawa, Koichi Nishioka, Hiroshi Kamio, Katsuhisa Usami
  • Patent number: 6117569
    Abstract: An SV sensor having a reference (pinned) layer formed of a first high uniaxial anisotropy ferromagnetic material, such as Co--Fe, and a keeper layer formed of a second high uniaxial anisotropy ferromagnetic material, such as Ni--Fe--Nb. Lapping induced stress in the high positive magnetostriction Co--Fe layer generates a uniaxial anisotropy field in the pinned layer resulting in enhanced pinned layer magnetization. This uniaxial anisotropy field adds to the exchange field from an antiferromagnetic layer resulting in a substantially increased pinning field over the pinning field from the exhange interaction alone. The added uniaxial anisotropy field also improves the stability of the SV sensor at elevated temperatures since the uniaxial field is determined by a Curie temperature significantly higher than the blocking temperatures of antiferromagnetic materials.
    Type: Grant
    Filed: May 27, 1998
    Date of Patent: September 12, 2000
    Assignee: International Business Machines Corporation
    Inventors: Tsann Lin, Daniele Mauri
  • Patent number: 6114850
    Abstract: A magnoresistance effect element made up of an anti-ferromagnetic layer, a fixed magnetic layer, a non-magnetic and a free magnetic layer, laminated successively onto a base layer. The ant-ferromagnetic layer is a layer film or multiple layer film comprising Ni oxide, Co oxide, or Fe oxide as a principal component, or a mixture of these. An adhesive layer for preventing peeling due to heat generated by the flow of current is provided between the base layer and the anti-ferromagnetic layer. By providing an adhesive layer between the base layer and the ferromagnetic layer in this way, the adhesive force between the base layer and the anti-ferromagnetic layer is increased, and therefore peeling does not occur, even if there are temperature changes in the magnetoresistance effect element.
    Type: Grant
    Filed: March 17, 1998
    Date of Patent: September 5, 2000
    Assignee: NEC Corporation
    Inventor: Kazuhiko Hayashi
  • Patent number: 6104189
    Abstract: A magnetoresistive spin valve sensor is described. Such a sensor is also known as a GMR sensor or giant magnetoresistive sensor. The layers (24, 26, 28) of the sensor are mounted on a substrate (20) having steps or terraces on one of its face. The steps or terraces on the substrate's surface cooperate with one or more of the ferromagnetic layers (24, 28) of the sensor to determine the layers' magnetic properties. Specifically, the thickness of one or more of the sensor's layers can be set above or below a critical thickness which determines whether the easy direction of uniaxial magnetization of a layer of that particular material is fixed or "pinned". If pinned, the layer has a high coercive field. Thus, the new device avoids a biasing layer to pin any of the magnetic layers. Preferably the easy axes of the first two ferromagnetic layers (24, 28) are set at 90.degree. to one another in the zero applied field condition by appropriate choice of layer thickness.
    Type: Grant
    Filed: June 10, 1998
    Date of Patent: August 15, 2000
    Assignee: International Business Machines Corporation
    Inventors: Rolf Allenspach, Wolfgang F. Weber
  • Patent number: 6104275
    Abstract: A magnetoresistive element is obtained which can exhibit a larger MR change than conventional.The magnetoresistive element is characterized as comprising a multilayer film 3 having a multilayer structure in which a nonmagnetic conductive layer 5 is interposed between a pair of ferromagnetic layer 4, 6, a pair of electrodes 7, 8 which produces a detection current flow through the multilayer film 3, and filter layers 1, 2 comprised of ferromagnetic material and disposed between at least one of the pair of ferromagnetic layers and the electrodes 7, 8 for delivering spin-polarized electrons to the ferromagnetic layers 4, 6, and characterized that a traveling distance of electrons in the ferromagnetic layers 4, 6 is maintained shorter than a spin diffusion length.
    Type: Grant
    Filed: March 18, 1999
    Date of Patent: August 15, 2000
    Assignee: Sanyo Electric Co., Ltd.
    Inventor: Atsushi Maeda
  • Patent number: 6100686
    Abstract: A magnetic field sensor has a substrate on which a plurality of resistive elements form a double Wheatstone bridge circuit, at least one of the resistive elements in each bridge having a magneto-resistive characteristic. The two bridges are identical except in that, if a given magneto-resistive element in a given branch in one bridge has a positive output polarity, then the corresponding magneto-resistive element in the same branch in the other bridge will have a negative output polarity. By adding the output signals of the two Wheatstone bridges a zero-point offset of the sensor can be determined and eliminated. There is no need to employ the so-called flipping technique employed for that purpose in conventional sensors, which requires increased power consumption.
    Type: Grant
    Filed: June 11, 1998
    Date of Patent: August 8, 2000
    Assignee: U.S. Philips Corporation
    Inventors: Martinus H. W. M. Van Delden, Kars-Michiel H. Lenssen, Marcellinus J. M. Pelgrom, Gerjan F. A. Van De Walle
  • Patent number: 6101071
    Abstract: A multi-layered magnetoresistance effect film, a magnetoresistance effect device and a magnetoresistance effect magnetic head of high sensitivity not affected by the sense current magnetic field. The multi-layered magnetoresistance effect film 1 includes a multi-layered film 4 of a pattern made up of magnetic layers 10 and non-magnetic electrically conductive layers 11, repeatedly layered together, and electrically conductive layers 3, 5 formed on at least one end face in the layering direction of the multi-layered film 4. The resistivity of the electrically conductive layers 3, 5 is selected to be larger than that of the magnetic layer 10. The magnetoresistance effect device has the above-defined multi-layered magnetoresistance effect film 1, while the magnetoresistance effect magnetic head has the above-defined magnetoresistance effect device.
    Type: Grant
    Filed: August 4, 1997
    Date of Patent: August 8, 2000
    Assignee: Sony Corporation
    Inventor: Akira Kouchiyama
  • Patent number: 6084405
    Abstract: A magnetoresistive transducer showing a giant magnetoresistance effect has a multi-layer structure including first and second ferromagnetic layers separated by a non-magnetic layer. The second ferromagnetic layer has a magnetization pinned in a direction perpendicular to a direction of a signal magnetic field. An anti-ferromagnetic layer adjacent to the second ferromagnetic layer pins magnetization of the second ferromagnetic layer in a direction perpendicular to a direction of a signal magnetic field so that magnetizations of the first and second ferromagnetic layers have components perpendicular to the signal magnetic field and those components are anti-parallel to each other.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: July 4, 2000
    Assignee: NEC Corporation
    Inventor: Tetsuhiro Suzuki
  • Patent number: 6077618
    Abstract: A magnetoresistance effect element, a head of the magnetoresistance effect type and a memory element in each of which a larger MR change can be acquired in a smaller magnetic field, and a method of producing the magnetoresistance effect element. In a magnetoresistance effect element, the basic structure comprises a lamination body of a magnetic layer/a nonmagnetic insulating layer/a magnetic layer, and a nonmagnetic insulating layer has, at an exposed part thereof, a conductive portion sufficiently smaller than the contact portion of the nonmagnetic insulating layer with respect to the magnetic layers, the conductive portion electrically connecting the magnetic layer to each other. Electrode lead portions are disposed at the upper and lower magnetic layers. In the lamination body, there may be formed, in the nonmagnetic insulating layer, a column-like conductive portion which is sufficiently smaller than the contact portion of the nonmagnetic insulating layer with respect to the magnetic layers.
    Type: Grant
    Filed: January 28, 1998
    Date of Patent: June 20, 2000
    Assignees: Shimadzu Corporation, Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Sakakima, Mitsuo Satomi, Shinji Nagamachi, Masahiro Ueda
  • Patent number: 6074767
    Abstract: Disclosed are spin valve magnetoresistive heads, air bearing sliders and magnetic storage systems employing spin valve magnetoresistive heads, and methods for fabricating spin valve magnetoresistive heads and air bearing sliders employing spin valve magnetoresistive heads. The spin valve magnetoresistive head in accordance with the present invention employs two antiferromagnetic films, one exchange-coupling to the reference layer in a first direction in the read region and the other exchange-coupling to the ferromagnetic film in a second direction substantially perpendicular to the first direction in the end regions. The exchange-coupled reference layer and the first antiferromagnetic film exhibit a blocking temperature equal to or greater than 300.degree. C. The exchange-coupled ferromagnetic/second antiferromagnetic films exhibit a blocking temperature equal to or greater than 200.degree. C. The two high blocking temperatures ensure thermal stabilty during sensor operation.
    Type: Grant
    Filed: March 12, 1998
    Date of Patent: June 13, 2000
    Assignee: International Business Machines Corporation
    Inventor: Tsann Lin
  • Patent number: 6075437
    Abstract: A magnetic field sensor device is disclosed comprising two substantially identical n-doped, high carrier mobility semiconductor films (e.g., InSb films) each containing a pattern of cylindrical holes or antidots that cause the resistance of the respective films to vary depending upon the direction of the in-plane component of an applied magnetic field.
    Type: Grant
    Filed: March 9, 1998
    Date of Patent: June 13, 2000
    Assignee: General Motors Corporation
    Inventors: Joseph Pierre Heremans, Jihui Yang
  • Patent number: 6075360
    Abstract: A magnetoresistive component and transducer for use therewith. The magnetoresistive component has a multilayer-type magnetoresistive strip bent in accordance with a repeated geometrical pattern (7a,7b). The pattern has at least one series of substantially parallel sections (7a,7b) for reducing the demagnetizing fields. The magnetoresistive strip (2) is formed from a stack (13) of magnetic metallic material layers (14) separated by non-magnetic metallic material layers (15). The magnetoresistive component is applicable to a transducer for reading information recorded in magnetic form or for detecting weak magnetic fields.
    Type: Grant
    Filed: August 24, 1994
    Date of Patent: June 13, 2000
    Assignee: Commissariat a l'Energie Atomique
    Inventors: Jean Mouchot, Jean-Marc Fedeli, Line Vieux-Rochaz, Marie-Helene Vaudaine
  • Patent number: 6074743
    Abstract: A magnetoresistance effect element according to the present invention comprises magnetic multilayer film having a non-magnetic metal layer, a ferromagnetic layer formed on one surface of the non-magnetic metal layer, a soft magnetic layer formed on the other surface of the non-magnetic metal layer, and a pinning layer which is formed on the ferromagnetic layer to pin a direction of magnetization of the ferromagnetic layer, wherein the ferromagnetic layer and the pinning layer are coupled to each other with epitaxial growth.Accordingly, the magnetoresistance device using the magnetoresistance effect element as described above exhibits an extremely large MR ratio and a linear rise-up characteristic of MR change in an extremely small range of applied magnetic field of about -10 to 10 Oe, and has high sensitivity to magnetic field, a large MR slope under a high-frequency magnetic field and an excellent heat resistance.
    Type: Grant
    Filed: July 17, 1998
    Date of Patent: June 13, 2000
    Assignee: TDK Corporation
    Inventors: Satoru Araki, Daisuke Miyauchi
  • Patent number: 6072382
    Abstract: A magnetic field sensor having a junction structure in a sensor cell using a dielectric intermediate separating material with two major surfaces on one of which is a base anisotropic ferromagnetic thin-film which is also on a base electrode, and on the other of which there is at least one of a plurality of separate anisotropic ferromagnetic thin-film but of differing rotational responses to external magnetic fields. Similar structures have a separated film in each that can be interconnected to one another with the interconnections extending at least in part substantially parallel to the widths of the separated films, and the separated films can have lengths with gradually narrowing widths to the ends thereof as can the base electrode. One or more planar coils can be supported at least in part on the separated films.
    Type: Grant
    Filed: January 6, 1999
    Date of Patent: June 6, 2000
    Assignee: Nonvolatile Electronics, Incorporated
    Inventors: James M. Daughton, Mark C. Tondra, Arthur V. Pohm
  • Patent number: 6069476
    Abstract: A magnetic field sensor having a magnetoresistance bridge. The sensor includes two longitudinally connected multilayer magnetoresistances and two transversely connected multilayer magnetoresistances. The two longitudinally connected magnetoresistances are sensitive to the magnetic field to be measured. The four magnetoresistances are connected to a wheatstone bridge.
    Type: Grant
    Filed: March 31, 1998
    Date of Patent: May 30, 2000
    Assignee: Commissariat A L'Energie Atomique
    Inventors: Line Vieux-Rochaz, Jean-Marc Fedeli, Robert Cuchet
  • Patent number: 6066947
    Abstract: A compact magnetic detection device with a high sensitivity. The device includes a single bias magnet producing a magnetic field to a gear having a magnetic substance, and a magnetoresistive effect element. The element is arranged so as to oppose the bias magnet and adjoin a pole face of the magnet on the gear's side. Further, the element is arranged in a plane substantially perpendicular to a moving direction of the gear, for producing resistance change caused by changes of magnetic field in response to the movement of the gear. Thus, the bias magnetic field existing in the moving direction of the gear is modulated to the direction facing the gear. Since a magnitude of modulation against the bias magnetic field amounts to a maximum in the vicinity of the pole face of the bias magnet on the gear's side, it is possible to realize the high sensitivity and furthermore, the magnetic detection device can be miniaturized by use of the single magnet.
    Type: Grant
    Filed: January 9, 1998
    Date of Patent: May 23, 2000
    Assignee: Yazaki Corporation
    Inventor: Shinichi Tamura
  • Patent number: 6063491
    Abstract: The invention provides a magnetoresistance effects film including (a) at least two thin magnetic films deposited on a substrate, (b) at least one thin nonmagnetic film interposed between the thin magnetic films, and (c) a thin antiferromagnetic film disposed adjacent to one of the thin magnetic films between which the thin nonmagnetic film is interposed. A bias magnetic field of one of the thin magnetic films induced by the thin antiferromagnetic film has an intensity Hr greater than a coercivity H.sub.C2 of the other of the thin magnetic films which is remote from the thin antiferromagnetic film (Hr>H.sub.C2). The thin antiferromagnetic film has a superlattice structure composed of at least two of NiO, Ni.sub.x Co.sub.1-x O(x=0.1-0.9) and CoO. A ratio of Ni relative to Co in the number of atoms in the superlattice structure is set equal to or greater than 1.0.
    Type: Grant
    Filed: March 11, 1998
    Date of Patent: May 16, 2000
    Assignee: NEC Corporation
    Inventors: Jun-Ichi Fujikata, Kazuhiko Hayashi, Hidefumi Yamamoto, Kunihiko Ishihara
  • Patent number: 6055135
    Abstract: The present invention aims to provide an excellent exchange coupling thin film consisting of a completely novel material other than FeMn or NiMn and having excellent corrosion resistance and high resistivity, and a magnetoresistive element and a magnetic head each of which include the exchange coupling thin film. The exchange coupling thin film includes an antiferromagnetic film mainly composed of a crystal phase of a body-centered cubic structure and containing Cr and element M where element M contains at least one element of the 3B group elements in the Periodic Table, or Al, Ga or In, and a ferromagnetic film containing at least one of Fe, Ne, and Co, both films being laminated in contact with each other, wherein magnetic exchange coupling is generated in the interface between the antiferromagnetic film and the ferromagnetic film.
    Type: Grant
    Filed: March 24, 1997
    Date of Patent: April 25, 2000
    Assignees: Alps Electric Co., Ltd., Kazuaki Fukamichi
    Inventors: Kazuaki Fukamichi, Yutaka Shimada, Osamu Kitakami, Kim Jek Jun, Hiroko Uyama, Akihiro Makino, Naoya Hasegawa
  • Patent number: 6048632
    Abstract: A self-biasing, non-magnetic giant magnetoresistive sensor having a Corbino-disk geometry constructed from a thin film of e.g., doped, Mercury Cadmium Telluride (MCT) Hg.sub.1-x Cd.sub.x Te exhibiting anomalously large Giant Magnetresistance (GMR) and zero field offset. In one embodiment, the sensor has a silicon substrate, a layer of doped, inhomogeneous MCT, and electrodes attached to the inhomogeneous layer. Alternatively, a buffer layer of, e.g., CdTe may overlay the substrate. In another embodiment, the sensor has a silicon substrate, a layer of doped, homogeneous MCT, and electrodes attached to the doped homogeneous MCT. Alternatively, a buffer layer of, e.g., CdTe may overlay the substrate as well. With constructed in as either of these embodiments, highly doped Corbino devices may show a significant zero-field offset in the GMR which results in a built-in bias field as high as 1500 G at T=300 K.
    Type: Grant
    Filed: August 22, 1997
    Date of Patent: April 11, 2000
    Assignees: NEC Research Institute, NEC Corporation
    Inventors: Stuart A. Solin, Tineke Thio, Masaya Kawano
  • Patent number: 6031273
    Abstract: A solid-state component is described which includes a network of thin-film elements. At least one thin-film element exhibits giant magnetoresistance. The network has a plurality of nodes, each of which represents a direct electrical connection between two of the thin-film elements. First and second ones of the plurality of nodes comprise power terminals. Third and fourth ones of the plurality of nodes comprise an output. A first conductor is inductively coupled to the at least one thin-film element for applying a first magnetic field thereto.
    Type: Grant
    Filed: December 8, 1998
    Date of Patent: February 29, 2000
    Assignee: Integrated Magnetoelectronics
    Inventors: E. James Torok, Richard Spitzer
  • Patent number: 6031372
    Abstract: Using a device (7) the magnetization distribution of the bias layer part (3) of a sensor element (E) is set. The sensor element has a thin-film structure (S) on a substrate (2) and has an increased magneto-resistive effect. The device (7) has an electrically conducting conductor part (L) and devices for positioning the conductor part (7) with regard to the sensor element (E). A predetermined setting current (I.sub.e) is carried over the conductor part (L), so the predetermined magnetization distribution can be set in a fixed manner in the bias layer part (3) of the sensor element (E).
    Type: Grant
    Filed: March 10, 1998
    Date of Patent: February 29, 2000
    Assignee: Siemens AG
    Inventor: Hugo Van Den Berg
  • Patent number: 6020738
    Abstract: The magnetizations of the bias-layer parts of several sensor elements interconnected to form a bridge are to be set using the present device. These sensor elements are arranged on a common substrate and display an increased magneto-resistive effect. The present device has several conductive-track parts in such an arrangement that, with a predetermined position of the conductive-track parts with respect to the sensor elements of the bridge circuit, in each case one conductive-track part is associated with at least one sensor element. A set current of a predetermined direction and strength is conducted over each conductive-track part in such a manner that a predetermined direction of orientation of the magnetization can be set in fixed manner in the bias-layer part of the corresponding associated sensor element.
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: February 1, 2000
    Assignee: Siemens Aktingesellschaft
    Inventors: Hugo Van Den Berg, Wolfgang Schelter
  • Patent number: 6012021
    Abstract: A microelectric position sensor wherein an assembly of magnetic field sensitive elements assume first and second states when subjected to a magnetic field having an intensity below or above first or second predetermined values respectively. A magnet is selectively movable relative to the assembly, so that the elements are selectively subjected to the magnetic field. The magnet has focusing tongues for focusing the magnetic field at a region including substantially only one of the elements, so that the magnetic field within the region has an intensity above the second value, and the magnetic field outside the region has an intensity below the first value.
    Type: Grant
    Filed: February 27, 1998
    Date of Patent: January 4, 2000
    Assignee: Microtronic A/S
    Inventors: Pirmin Rombach, Lars J. Stenberg
  • Patent number: 6004654
    Abstract: In a magnetoresistance multilayer film comprising at least two magnetic layers on a substrate, with a nonmagnetic layer intervening between the magnetic layers, each interface between the magnetic layer and the nonmagnetic layer is corrugated in both X and Y directions of a substrate major surface. The corrugations of the interface are formed by providing the substrate surface with a multiplicity of asperities distributed in both X and Y directions and depositing magnetic layers and nonmagnetic layers thereon. The film shows a linear rise of MR change in an applied magnetic field within a very low range of 0 to about 40 Oe.
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: December 21, 1999
    Assignees: TDK Corporation, Teruya Shinjo
    Inventors: Teruya Shinjo, Satoru Araki
  • Patent number: 5998016
    Abstract: A spin valve effect MR sensor includes a spin valve effect multi-layered structure. This structure has a first thin film layer of ferromagnetic material with one and the other surfaces, a second thin film layer of ferromagnetic material with one and the other surfaces, a thin film spacer layer of nonmagnetic conductive material deposited between the one surfaces of the first and second ferromagnetic material layers, a thin film layer of anti-ferromagnetic material deposited on the other surface of the second ferromagnetic material layer, for pinning the second ferromagnetic material layer, a thin film layer of anti-diffusion material deposited on the other surface of the first ferromagnetic material layer, and a thin film current bypass layer of nonmagnetic conductive material deposited on the thin film anti-diffusion material layer.
    Type: Grant
    Filed: January 13, 1998
    Date of Patent: December 7, 1999
    Assignee: TDK Corporation
    Inventors: Tetsuro Sasaki, Noriyuki Ito
  • Patent number: 5989690
    Abstract: Magnetic thin films 2 and 3 are stacked on a substrate 4 with a nonmagnetic thin film 1 interposed therebetween. An antiferromagnetic thin film 5 is arranged adjacent to one magnetic thin film 3. The inequality Hc.sub.2 <Hr is satisfied between a bias magnetic field Hr of the antiferromagnetic thin film 5 and coercive force Hc.sub.2 of the other magnetic thin film 2. At least a part of the antiferromagnetic thin film 5 comprises NiMn of an fct structure. Alternatively, the antiferromagnetic thin film 5 comprises a two-layer structure composed of a CoO layer deposited on a NiO layer to a thickness between 10 and 40 angstroms.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: November 23, 1999
    Assignee: NEC Corporation
    Inventors: Jun-Ichi Fujikata, Kazuhiko Hayashi, Hidefumi Yamamoto, Kunihiko Ishihara, Masafumi Nakada
  • Patent number: 5989691
    Abstract: A magnetic element comprising a thin film having a uniaxial magnetic anisotropy partly disposed on a polymer substrate. The magnetic element exhibits a discontinuous magnetic reversal under an applied magnetic field having a magnitude that is not smaller than a predetermined value. Despite its simple structure, the magnetic element exhibits excellent magnetic characteristics. Furthermore, the magnetic element exhibits little variation in magnetic characteristics and its magnetic characteristics are therefore high reproducible.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: November 23, 1999
    Assignee: Unitika Ltd.
    Inventors: Shinji Furukawa, Nobuyoshi Yano
  • Patent number: 5982177
    Abstract: A magnetic sensor for detecting the presence of a magnetic sample proximate a sensing region. A magnetoresistive element is positioned in a biasing region of the sensor which is spaced apart from the sensing region. A magnetic circuit provides a magnetic field to the sensing region and the biasing region. The magnetic field biases the magnetoresistive element positioned in the biasing region. A circuit detects changes in the magnetic field in the biasing region as a function of changes in the resistance of the magnetoresistive element whereby changes in the magnetic field caused by the presence of a magnetic sample proximate the sensing region are detected.
    Type: Grant
    Filed: August 8, 1997
    Date of Patent: November 9, 1999
    Assignee: Florida State University
    Inventor: Fred J. Cadieu
  • Patent number: 5982178
    Abstract: A method and apparatus for sensing a desired component of a magnetic field using an isotropic magnetoresistive material. This is preferably accomplished by providing a bias field that is parallel to the desired component of the applied magnetic field. The bias field is applied in a first direction relative to a first set of magnetoresistive sensor elements, and in an opposite direction relative to a second set of magnetoresistive sensor elements. In this configuration, the desired component of the incident magnetic field adds to the bias field incident on the first set of magnetoresistive sensor elements, and subtracts from the bias field incident on the second set of magnetoresistive sensor elements. The magnetic field sensor may then sense the desired component of the incident magnetic field by simply sensing the difference in resistance of the first set of magnetoresistive sensor elements and the second set of magnetoresistive sensor elements.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: November 9, 1999
    Assignee: Honewell Inc.
    Inventors: Bharat B. Pant, Hong Wan
  • Patent number: 5976681
    Abstract: A magnetoresistive multilayer structure having ferromagnetic layers of Co codeposited with Cu. The codeposited layer has a total thickness between 1 and 20 .ANG.. The volume of Cu in the codeposited layers is between 1% and 120% of the volume of Co. The ferromagnetic layers are separated by layers of Cu. The resulting structure has low magnetoresistive hysteresis.
    Type: Grant
    Filed: June 30, 1997
    Date of Patent: November 2, 1999
    Assignee: Ford Global Technologies, Inc.
    Inventors: Henry Holloway, David John Kubinski
  • Patent number: 5966272
    Abstract: A magnetoresistive (MR) read transducer having an exchange layer adjacent a soft adjacent layer (SAL). The exchange layer generates a transverse bias field which saturates the SAL with little or no sense current.
    Type: Grant
    Filed: June 21, 1993
    Date of Patent: October 12, 1999
    Assignee: Read-Rite Corporation
    Inventor: William Charles Cain
  • Patent number: 5965283
    Abstract: The low-field magnetoresistance of a high carrier mobility semiconductor with inhomogeneities which are more conducting than the surrounding semiconductor material matrix is significantly enhanced compared to the magnetoresistance of the homogeneous material. The enhancement results from a magnetic field induced geometric effect in which current is expelled from the conducting inhomogeneity. The enhanced giant magnetoresistance is demonstrated at low field in (near) zero-band-gap material, such as Hg.sub.1-x Cd.sub.x Te(x.about.0.1). The effect is applied to the fabrication of magnetic read head sensors such as Corbino disc, bar magnetoresistance sensors and thin film sensors.
    Type: Grant
    Filed: December 23, 1997
    Date of Patent: October 12, 1999
    Assignee: NEC Research Institute, Inc.
    Inventors: Stuart A. Solin, Tineke Thio
  • Patent number: 5965840
    Abstract: A magnetoresistive sensor in the magnetic storage device includes a magnetoresistive element for sensing magnetic fields carried on storage medium. A cooling device is thermally coupled to the magnetoresistive element and arranged to conduct heat in a direction away from the magnetoresistive element to thereby cool the magnetoresistive element during normal operation of the storage device.
    Type: Grant
    Filed: May 28, 1997
    Date of Patent: October 12, 1999
    Assignee: Seagate Technology, Inc.
    Inventors: Subra Nagarajan, Ramesh Sundaram, Mary Cynthia Hipwell, Clifton H. K. Chang
  • Patent number: 5966275
    Abstract: A GMR magnetic sensor includes a lower electrode, a first non-magnetic metal layer formed on the lower electrode and including ferromagnetic regions, a second non-magnetic metal layer on the first non-magnetic metal layer, a third non-magnetic metal layer on the second non-magnetic metal layer and including ferromagnetic regions, and an upper electrode formed on the third non-magnetic metal layer, wherein a tunneling insulation film is disposed further between the first non-magnetic metal layer and the third non-magnetic metal layer.
    Type: Grant
    Filed: February 13, 1998
    Date of Patent: October 12, 1999
    Assignee: Fujitsu Limited
    Inventor: Makoto Iijima
  • Patent number: 5952825
    Abstract: An integrated magnetic field sensing device has magnetic field sensing elements arranged in an electrical bridge. A first spiral coil provides a setting and resetting function. Second and third coils are arranged to carry a common current and produce magnetic fields useful for test, compensation, calibration, and feedback applications.
    Type: Grant
    Filed: August 14, 1997
    Date of Patent: September 14, 1999
    Assignee: Honeywell Inc.
    Inventor: Hong Wan
  • Patent number: 5948553
    Abstract: A spin valve type multilayered magnetic structure has Fe-base soft magnetic crystalline layer having a mean grain size equal to or less than 30 nanometers and sandwiching a non-magnetic spacer layer, and the Fe-base soft magnetic crystalline layer is expressed as Fe-M-B where M is at least one transition metal selected from the group consisting of Sc, Ti, V, Cr, Y, Zr, Nb, Mo, La, Hf, Ta and W and B is selected from the group consisting of C, B and N; and the spin valve type multilayered magnetic structure achieves a large magnetoresistance ratio equal to or greater than 10.
    Type: Grant
    Filed: April 25, 1997
    Date of Patent: September 7, 1999
    Assignee: NEC Corporation
    Inventor: Atsushi Kamijo
  • Patent number: 5945904
    Abstract: A giant magnetoresistive assembly includes a first film fabricated of a ferromagnetic material having a first predetermined thickness, a second film fabricated of a non-ferromagnetic material formed to said first film having a second predetermined thickness greater than said first predetermined thickness, and a third film fabricated of a ferromagnetic material formed to the second film having a third predetermined thickness wherein the third predetermined thickness differs from the first predetermined thickness.
    Type: Grant
    Filed: September 6, 1996
    Date of Patent: August 31, 1999
    Assignee: Ford Motor Company
    Inventors: David John Kubinski, Henry Holloway
  • Patent number: 5945825
    Abstract: A magnetic field-sensitive sensor device contains two branch circuits having a plurality of GMR sensor elements, each of whose thin-film structure has a bias layer portion. At least one pair of sensor elements should have magnetizations of their bias layer portions that have at least essentially an opposite orientation relative to each other and thereby define a reference direction. At least one additional sensor element has a magnetization of its bias layer portion that forms a predetermined angle with the reference direction.
    Type: Grant
    Filed: May 15, 1997
    Date of Patent: August 31, 1999
    Assignee: Siemens Aktiengesellschaft
    Inventor: Wolfgang Clemens
  • Patent number: 5936400
    Abstract: The displacement sensor employing a magnetoresistive effect laminate structure consisting of a bottom ferromagnetic layer with a field oriented in one direction, a middle non-magnetic layer, and a top softer magnetic layer. The top softer magnetic layer has two regions of opposing magnetic fields separated by a domain wall, where the magnetic field in one region is aligned with the bottom layer magnetic field. The resistance of the laminate structure changes as the location of the domain wall changes. In one improvement, the domain wall is induced by a pair of opposing semicylindrical magnets magnetized along their semicylindrical surface, forming parallel field lines and leading to a stronger domain wall. In another improvement, there are four laminate structures in an electrical bridge configuration. The bridge is excited by an alternating current source and the output is synchronously measured.
    Type: Grant
    Filed: December 23, 1996
    Date of Patent: August 10, 1999
    Assignee: Federal Products Co.
    Inventors: Igor Tchertkov, Jon Klinkhamer
  • Patent number: 5936402
    Abstract: Two magnetic layers are mutually interconnected by a constricted region also made of a magnetic material. The layers may be separated by an intermediate non-metallic layer having a hole filed with magnetic material to from the constricted region. Alternatively, the layers and constricted region may be substantially co-planar. The constricted region minimum cross-section dimension preferably is less than one micron, and ideally of the order of 100 nm, thus being much smaller than the diameter of a magnetic domain. A high magneto-resistance ratio is obtained, and electrical and magnetic properties of the sensor can be adjusted largely independently.
    Type: Grant
    Filed: June 11, 1997
    Date of Patent: August 10, 1999
    Assignee: U.S. Philips Corporation
    Inventors: Cornelis M. Schep, Martinus A.M. Gijs
  • Patent number: 5932310
    Abstract: A magnetic element comprising a first thin film and a second thin film having a coercive force that is greater than the coercive force of the first thin film formed on a substrate. The magnetic element exhibits a continuous magnetic reversal under an applied alternating magnetic field having a magnitude that is smaller than the coercive force of the second thin film to cause said first thin film to undergo magnetic reversal. The magnetic element also exhibits a discontinuous sudden magnetic reversal under an applied alternating magnetic field having a magnitude that is greater than the coercive force of the second thin film. The configuration of the magnetic element has little effect on discontinuous magnetization response. Thus the magnetic element exhibits good magnetic characteristics even when formed in a small size.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: August 3, 1999
    Assignee: Unitika Ltd.
    Inventors: Shinji Furukawa, Nobuyoshi Yano
  • Patent number: 5925919
    Abstract: A CMOS semiconductor structure and a process for producing the structure permit particularly simple, self-aligned contact-hole etching. Magnetoresistors are fully encased by a nitride layer and a lateral covering, so that the magnetoresistors are protected even in the event of misaligned contact-hole etching. The magnetoresistors, which are formed from a polysilicon layer, are etched back laterally by isotropic etching and a dielectric layer is conformally deposited so that the etched-back magnetoresistor region is thereby filled. The dielectric layer is then removed again by isotropic etching outside the etched-back magnetoresistor regions.
    Type: Grant
    Filed: June 4, 1997
    Date of Patent: July 20, 1999
    Assignee: Siemens Aktiengesellschaft
    Inventor: Martin Kerber