Patents Represented by Attorney Otto Schmid, Jr.
  • Patent number: 5341118
    Abstract: A multilayer magnetoresistive (MR) sensor formed on a substrate includes alternating layers of a ferromagnetic material and a non-magnetic metallic material. The ferromagnetic material and the non-magnetic material form bilayers which exhibit the property that the magnetoresistance of the multilayered structure oscillates as a function of thickness of the non-magnetic material. A current flow is produced through the MR sensor, and the variations in the resistivity of the MR sensor are sensed as a function of the magnetic field being sensed.
    Type: Grant
    Filed: May 6, 1993
    Date of Patent: August 23, 1994
    Assignee: International Business Machines Corporation
    Inventors: Stuart S. P. Parkin, Kevin P. Roche
  • Patent number: 5264981
    Abstract: A soft magnetic film includes a laminated structure having an alternating plurality of first magnetic and second magnetic film. The first magnetic films is of a predetermined thickness range and is made of a magnetic alloy of nickel, iron and nitrogen with the nitrogen present from greater than zero to 20 atomic percent. The second magnetic film is of a predetermined thickness range and is made of a magnetic alloy of iron and nitrogen with the nitrogen present from greater than zero to about 20 atomic percent. The films can be annealed in an applied magnetic field. The multilayer films have application as pole pieces and shields in magnetic heads. The magnetic heads are for use in dynamic storage systems including disk and tape media.
    Type: Grant
    Filed: August 14, 1991
    Date of Patent: November 23, 1993
    Assignee: International Business Machines Corporation
    Inventors: Richard T. Campbell, Jyh-Shuey J. Lo
  • Patent number: 5262914
    Abstract: A magnetoresistive (MR) read transducer in which a layered structure comprising an MR layer, an antiferromagnetic material in direct contact with the MR layer and a thin layer of interdiffusion material in contact with the layer of antiferromagnetic material is subjected to a heating process to a temperature within a chosen temperature for a chosen time to form a magnetic interface between the antiferromagnetic material the MR layer. The magnetic interface produces a high level of exchange bias with the MR layer.
    Type: Grant
    Filed: October 18, 1991
    Date of Patent: November 16, 1993
    Assignee: International Business Machines Corporation
    Inventors: Mao-Min Chen, Ching H. Tsang
  • Patent number: 5206590
    Abstract: A magnetoresistive (MR) sensor comprising a first and a second thin film layer of a magnetic material separated by a thin film layer of a non-magnetic metallic material. The first ferromagnetic layer is magnetically soft. The magnetization direction of the first layer of magnetic material is set substantially perpendicular to the magnetization of the second layer of magnetic material at zero applied field, and the magnetization direction of the second layer of magnetic material is fixed. A current flow is produced through the MR sensor, and the variations in voltage across the MR sensor are sensed due to changes in resistance of the MR sensor produced by rotation of the magnetization in the first layer of magnetic material as a function of the magnetic field being sensed. The variation of the resistance with the angle between the magnetizations of the first and second layers of magnetic material has been defined as the spin valve (SV) effect.
    Type: Grant
    Filed: December 11, 1990
    Date of Patent: April 27, 1993
    Assignee: International Business Machines Corporation
    Inventors: Bernard Dieny, Bruce A. Gurney, Steven E. Lambert, Daniele Mauri, Stuart S. P. Parkin, Virgil S. Speriosu, Dennis R. Wilhoit
  • Patent number: 5198090
    Abstract: A sputtering apparatus for coating a substrate comprising a first electrode for supporting a target material and a second electrode for supporting a substrate, upon which the coating is deposited. A source of RF power is connected to impose an RF voltage across the electrodes to produce a glow discharge in the space between the electrodes, and shutter means is provided in the space between the electrodes. The shutter means has means for blocking a substantial part of the sputtered atoms from the target electrode glow discharge traveling at or near normal incidence and at least one opening shaped to permit a substantial part of the sputtered atoms from the target electrode traveling at an oblique angle to impinge upon the substrate to produce a thin film coating of the target material.
    Type: Grant
    Filed: December 6, 1991
    Date of Patent: March 30, 1993
    Assignee: International Business Machines Corporation
    Inventors: Arkadi Galicki, Cheng T. Horng, Robert O. Schwenker
  • Patent number: 5175658
    Abstract: A magnetic head slider having a protective coating on the rails thereof, the protective coating comprising a thin adhesion layer, a thin layer of amorphous hydrogenated carbon, and a thin masking layer. The protective coating is deposited on the air bearing surface of the slider after the thin film magnetic heads are lapped to a chosen dimension, but before the pattern of rails is produced on the air bearing surface. The protective coating protects the magnetic head during the rail fabrication process and in usage in a magnetic recording system protects the magnetic head from wear and corrosion damage.
    Type: Grant
    Filed: December 27, 1990
    Date of Patent: December 29, 1992
    Assignee: International Buiness Machines Corporation
    Inventors: Henry C. Chang, Mao-Min Chen, Cheng T. Horng, Robert O. Schwenker
  • Patent number: 5164869
    Abstract: An integrated inductive write, magnetoresistive (MR) read thin film magnetic head comprising an open magnetic yoke having outside legs each having a winding thereon and a central leg having an opening across which the MR element is coupled. The outer legs are overlapped at one end to form confronting pole pieces having a transducing gap between the pole pieces, and the central leg is positioned between the pole pieces at one end and joined with the outer legs at the other end to form a symmetrical magnetic yoke structure. The windings are wound in a direction so that the flux produced by equally energizing the windings is equal and opposite in each of the outside legs, is additive at the transducing gap between the pole pieces, and produces no net flux through the central leg.
    Type: Grant
    Filed: February 27, 1991
    Date of Patent: November 17, 1992
    Assignee: International Business Machines Corporation
    Inventors: Robert E. Fontana, Jr., Lubomyr T. Romankiw, Mason L. Williams, III
  • Patent number: 5161133
    Abstract: A magneto-optical (M-O) storage detection channel which includes optical means for detecting edge transitions between magneto-optical domains. The beam returning from the storage medium is analyzed both spatially and in polarization. When a transition is centered under the read laser beam, the spatial reversal in the sign of the amplitude of the signal polarization due to the spatially nonuniform Kerr rotation is compensated by a reversal due to spatially nonuniform (split) detectors or a matched optical filter. The optical powers on the two sides of each split detectors or on two independent detectors sensitive to orthogonal polarizations become unequal thereby producing an electrical signal signal which comprises spaced peaks in opposite directions at the leading and trailing edges of the M-O domain or mark.
    Type: Grant
    Filed: June 25, 1991
    Date of Patent: November 3, 1992
    Assignee: International Business Machines Corporation
    Inventor: Marc D. Levenson
  • Patent number: 5159508
    Abstract: A magnetic head slider having a protective coating on the rails thereof, the protective coating comprising a thin adhesion layer and a thin layer of amorphous hydrogenated carbon. The protective coating is deposited on the air bearing surface of the slider after the thin film magnetic heads are lapped to a chosen dimension, but before the pattern of rails is produced on the air bearing surface. The protective coating protects the magnetic head during the rail fabrication process and in usage in a magnetic recording system protects the magnetic head from wear and corrosion damage.
    Type: Grant
    Filed: December 27, 1990
    Date of Patent: October 27, 1992
    Assignee: International Business Machines Corporation
    Inventors: Alfred Grill, Cheng T. Horng, Bernard S. Meyerson, Vishnubhai V. Patel, Michael A. Russak
  • Patent number: 5159513
    Abstract: A magnetoresistive (MR) sensor comprising a layered structure formed on a substrate includes a first and a second thin film layer of magnetic material separated by a thin film layer of non-magnetic metallic material such as Cu, Au, or Ag, with at least one of the layers of ferromagnetic material formed of either cobalt or a cobalt alloy. The magnetization direction of the first ferromagnetic layer, at zero applied field, is set substantially perpendicular to the magnetization direction of the second ferromagnetic layer which is fixed in position. A current flow is produced through the sensor, and the variations in voltage across the MR sensor are sensed due to the changes in resistance produced by rotation of the magnetization in the front layer of ferromagnetic material as a function of the magnetic field being sensed.
    Type: Grant
    Filed: February 8, 1991
    Date of Patent: October 27, 1992
    Assignee: International Business Machines Corporation
    Inventors: Bernard Dieny, Bruce A. Gurney, Serhat Metin, Stuart S. P. Parkin, Virgil S. Speriosu
  • Patent number: 5155642
    Abstract: A magnetoresistive (MR) read transducer comprising an MR layer having longitudinally magnetized end regions separated by a central active region and a soft magnetic biasing layer parallel to but spaced from the MR layer. The easy axes of the MR layer and the soft magnetic biasing layer are tilted at a small angle with respect to the longitudinal axis of the transducer and these angles are substantially equal, but in the opposite sense.
    Type: Grant
    Filed: June 11, 1991
    Date of Patent: October 13, 1992
    Assignee: International Business Machines Corporation
    Inventor: Otto Voegeli
  • Patent number: 5117320
    Abstract: A magnetic head device comprising a magnetic core member made from a magnetic material having a positive magnetostriction constant and having confronting pole pieces separated by a non-magnetic material to form a transducing gap. A coil is wound around the magnetic core member so that a read signal can be read out from the coil, and a d.c. bias magnetic field is generated in the magnetic core member when a read signal is read out from the coil so that distortion of the read signal is suppressed.
    Type: Grant
    Filed: October 4, 1990
    Date of Patent: May 26, 1992
    Assignee: International Business Machines Corporation
    Inventors: Kenji Ogasawara, Koji Kurachi, Atsushi Tobari
  • Patent number: 5114913
    Abstract: A slider assembly for supporting a magnetic head a small uniform spacing above the surface of a magnetic recording medium comprising a slider body having a layer of superconducting material on the surface of the slider assembly which faces the surface of the magnetic recording medium. The slider assembly is maintained in a vacuum of a predetermined level or in a predetermined gas, and the slider assembly is cooled to a temperature below the critical temperature of the superconductor material so that the slider assembly and the magnetic transducer are levitated to a small uniform spacing above the surface of the magnetic recording medium due to magnetic forces between the magnetized magnetic recording medium and the layer of superconducting material.
    Type: Grant
    Filed: April 30, 1990
    Date of Patent: May 19, 1992
    Assignee: International Business Machines Corporation
    Inventors: Hans J. Coufal, Mason L. Williams, III
  • Patent number: 5079663
    Abstract: A magnetoresistive (MR) sensor is center tapped to provide the difference signals for servo operation on data and sum signals for the data information. The center-tap of the MR sensor is made of a high resistivity material compared to the resistivity of the MR element itself such as tantalum, Nichrome and carbon. Processes which can be used to produce the high resistivity center-tap conductor include an insulator layer to define both the track width and the center-tap conductor and a sequence which first patterns the MR sensor and then masks to define the conductor regions.
    Type: Grant
    Filed: January 29, 1990
    Date of Patent: January 7, 1992
    Assignee: International Business Machines Corporation
    Inventors: Kochan Ju, Mohamad T. Krounbi, Po-Kang Wang
  • Patent number: 5079035
    Abstract: A magnetoresistive (MR) read transducer having passive end regions separated by a central active region in which an MR layer is formed which extends over substantially only the central active region and in which a hard magnetic layer is formed in each end region. The hard magnetic layers form an abutting junction having electrical and magnetic continuity with the MR layer to produce a longitudinal bias in the MR sensor. The transducer is produced by a method in which the same stencil defines the extent of both the MR layer and the hard magnetic layers so that the abutting junctions are formed easily and reliably.
    Type: Grant
    Filed: December 18, 1990
    Date of Patent: January 7, 1992
    Assignee: International Business Machines Corporation
    Inventors: Mohamad T. Krounbi, Otto Voegeli, Po-Kang Wang
  • Patent number: 5059989
    Abstract: A thermal drop-on-demand ink jet print head in which conductor electrodes are formed on opposed surfaces of a print head substrate and extend to the edge of the substrate. An array of heater elements is formed on the edge of the substrate in electrical contact with the conductor electrodes. A nozzle plate is mounted with a nozzle aligned with each heater element, and a manifold is positioned to provide ink to the space between the nozzle plate and the edge of the substrate so that a drop of ink can be ejected from the nozzle each time the associated heater element is energized with a data pulse applied to a selected one of the conductor electrodes.
    Type: Grant
    Filed: May 16, 1990
    Date of Patent: October 22, 1991
    Assignee: Lexmark International, Inc.
    Inventors: Jerome M. Eldridge, Gary S. Keller, Francis C. Lee, Graham Olive
  • Patent number: 5032935
    Abstract: A circuit for producing a signal whose magnitude is a chosen amplitude compensation characteristic of the signals produced by a magnetoresistive (MR) element comprising an input stage which produces an amplified output signal which is coupled to the output stage, and control signals proportional to the resistance of the MR element and inversely proportional to the resistance of the MR element which are coupled to a feedforward circuit. The feedforward circuit generates a chosen amplitude equalization characteristic of the signals coupled to the feedforward circuit, and this signal is coupled to a bias terminal of the output stage so that the output stage produces a signal representing the chosen amplitude compensation characteristic of the signals produced by the MR element.
    Type: Grant
    Filed: December 12, 1989
    Date of Patent: July 16, 1991
    Assignee: International Business Machines Corporation
    Inventors: Stephen A. Jove, Klaas B. Klaassen, Long Tran
  • Patent number: 5026470
    Abstract: A sputtering apparatus in which the electrode for supporting the substrates upon which thin magnetic films are to be deposited has a polygon-shaped planar coil adjacent to a surface so that the coil can be energized to produce a uniform magnetic field at the surface of the substrates which is oriented normal to the polygon faces of the coil. This apparatus produces uniform easy axis of the thin magnetic films deposited on the substrates during relative motion between the substrates and the target electrode.
    Type: Grant
    Filed: December 19, 1989
    Date of Patent: June 25, 1991
    Assignee: International Business Machines
    Inventors: Peter I. Bonyhard, David C. Cheng, William J. Glover, Howard A. Hendrix, Ernest S. Ward, John W. Williams
  • Patent number: 5018037
    Abstract: A magnetoresistive (MR) read transducer having passive end regions separated by a central active region in which an MR layer is formed which extends over substantially only the central active region and in which a hard magnetic layer is formed in each end region. The hard magnetic layers form an abutting junction having electrical and magnetic continuity with the MR layer to produce a longitudinal bias in the MR sensor. The transducer is produced by a method in which the same stencil defines the extent of both the MR layer and the hard magnetic layers so that the abutting junctions are formed easily and reliably.
    Type: Grant
    Filed: October 10, 1989
    Date of Patent: May 21, 1991
    Inventors: Mohamad T. Krounbi, Otto Voegeli, Po-Kang Wang
  • Patent number: 5014147
    Abstract: An improved thin film magnetoresistive (MR) sensor uses an alloy comprising Fe.sub.(1-x) Mn.sub.x, where x is within the range of 0.3 to 0.4, as an antiferromagnetic layer to provide longitudinal exchange bias in the ferromagnetic MR layer. In a specific embodiment the exchange bias is at a high level and is independent of thickness of the antiferromagnetic layer over a wide range.
    Type: Grant
    Filed: October 31, 1989
    Date of Patent: May 7, 1991
    Assignee: International Business Machines Corporation
    Inventors: Stuart S. P. Parkin, Kevin P. Roche, Virgil S. Speriosu