Patents Represented by Attorney Lewis L. Nunnelley
  • Patent number: 7191508
    Abstract: A method for manufacturing thin-film magnetic head sliders is disclosed. Initially, an elastic layer, which may be made of poly-dimethyl siloxane (PDMS), is spun on a wafer and is thermally cured. Then, a resist layer is spun on the elastic layer. Both the resist layer and the elastic layer are subsequently peeled off together from the wafer. Next, the peeled resist layer/elastic layer is applied onto a group of magnetic heads with the resist layer in direct contact with the magnetic heads. Finally, the elastic layer is peeled off from the resist layer such that the resist layer remains attaching to the magnetic heads.
    Type: Grant
    Filed: August 13, 2004
    Date of Patent: March 20, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Cherngye Hwang, Kim Y. Lee, Gary McClelland, Dennis Richard McKean, Timothy Clark Reiley
  • Patent number: 7082017
    Abstract: A spin valve sensor includes a spacer layer which is located between a free layer and an antiparallel (AP) pinned layer structure wherein the AP pinned layer structure includes an antiparallel coupling layer which is located between and interfaces first and second AP pinned layers with the second AP pinned layer interfacing the spacer layer. Each of the first and second AP pinned layers is composed of cobalt iron (CoFe) wherein the iron (Fe) content in the cobalt iron (CoFe) of one of the first and second AP pinned layers is greater than the iron (Fe) content in the cobalt iron (CoFe) in the other one of the first and second AP pinned layers.
    Type: Grant
    Filed: April 26, 2004
    Date of Patent: July 25, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, Hardayal Singh Gill, Mustafa Pinarbasi
  • Patent number: 7075760
    Abstract: A magnetic head assembly includes a read head with a current perpendicular to the planes (CPP) sensor. The CPP sensor includes an AP pinned layer structure, a free layer and a spacer layer which is located between the free layer and the AP pinned layer structure. An in-stack longitudinal biasing structure for longitudinally biasing the free layer includes a pinned layer, an AFM pinning layer for pinning the pinned layer and a ruthenium spacer layer which is located between the pinned layer and the free layer. The free layer includes first and second free films with the first free film being iron and interfacing the spacer layer. The second free film may be nickel iron for imparting magnetic softness to the first free film. The pinned layer and a second AP pinned layer of the free layer structure may also be iron. The iron content of the layers in the sensor and the ruthenium spacer layer significantly increase the magnetoresistive coefficient dr/R of the CPP sensor.
    Type: Grant
    Filed: August 31, 2004
    Date of Patent: July 11, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7064938
    Abstract: A method makes a spin valve sensor of a magnetic read head which includes the steps of forming a ferromagnetic pinned layer structure that has a magnetic moment, forming a pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure, forming a free layer structure, forming a nonmagnetic electrically conductive spacer layer between the free layer and the pinned layer structure and the forming of the free layer structure including the step of sputter depositing at least a first free layer composed of cobalt iron directly on the spacer layer in a nitrogen atmosphere.
    Type: Grant
    Filed: August 31, 2004
    Date of Patent: June 20, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Mustafa Pinarbasi
  • Patent number: 7001499
    Abstract: A process for electroplating and annealing thin-films of nickel-iron alloys having from 63% to 81% iron content by weight to produce pole pieces having saturation flux density (BS) in the range from 1.9 to 2.3 T (19 to 23 kG) with acceptable magnetic anisotropy and magnetostriction and a coercivity (HC) no higher than 160 A/m (2 Oe). The desired alloy layer properties, including small crystal size and minimal impurity inclusions, can be produced by including higher relative levels of Fe++ ions in the electroplating bath while holding the bath at a lower temperature while plating from a suitable seed layer. The resulting alloy layer adopts a small crystal size (BCC) without significant inclusion of impurities, which advantageously permits annealing to an acceptable HC while retaining the high BS desired.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: February 21, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Mike Ming Yu Chen, Thomas Edward Dinan, April Hixson-Goldsmith, Murali Ramasubramanian, Neil Leslie Robertson
  • Patent number: 6950260
    Abstract: A magnetic recording system is provided having a write head employing a combination of magnetic write field gradient and thermal gradient to write data on a ‘thermal spring’ magnetic recording media. The write head comprises a magnetic element using a write current to induce a magnetic write field at the magnetic media and a thermal element using a very small aperture laser to heat a portion of the media. The thermal spring magnetic media comprises [comprises] first and second stacks providing two exchange coupled ferromagnetic layers having different Curie temperatures [The first stack has a high magneto-crystalline anisotropy, a relatively low saturation magnetization and a low Curie temperature.] [The second stack has a relatively low magneto-crystalline anisotropy, a high saturation magnetization and a high Curie temperature.
    Type: Grant
    Filed: June 4, 2001
    Date of Patent: September 27, 2005
    Assignee: Hitachi Global Technologies Netherlands B.V.
    Inventors: Kevin Robert Coffey, Robert Edward Fontana, Jr., Jan-Ulrich Thiele
  • Patent number: 6930866
    Abstract: A magnetic tunnel junction (MTJ) sensor in which the free layer longitudinal biasing elements are coupled, without insulation, to the free layer outside of the MTJ stack to provide reliable non-shunting MTJ free layer stabilization without extremely thin dielectric layers. In one embodiment, hard magnetic (HM) layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In another embodiment, antiferromagnetic (AFM) bias layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In other embodiments, nonconductive HM layers are disposed either in contact with the free layer outside of the MTJ stack active region and/or in abutting contact with the MTJ stack active region.
    Type: Grant
    Filed: July 16, 2003
    Date of Patent: August 16, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Wipul Jayasekara
  • Patent number: 6927948
    Abstract: A differential current-perpendicular-to-the-plane (CPP) giant magnetoresistive (GMR) sensor is provided having nonmagnetic high conductivity leads to achieve low lead resistance. The differential CPP GMR sensor comprises a first spin valve (SV) sensor, a second SV sensor and a metal gap layer disposed between the first and the second SV sensors. Because of the differential operation of the CPP GMR sensor of this invention, there is no need for shield layers to screen the sensor from stray magnetic fields. The shield layers are replaced with thick nonmagnetic lead layers having high conductivity to reduce the lead resistance of the sensor. Suitable materials for forming the leads include tungsten (W), gold (Au), rhodium (Rh), copper (Cu) and tantalum (Ta) because of their conductivity properties and because they are robust with respect to corrosion and smearing.
    Type: Grant
    Filed: January 23, 2003
    Date of Patent: August 9, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 6919280
    Abstract: During manufacture, a magnetoresistive sensor having a ferromagnetic free layer is commonly provided with a tantalum cap layer. The tantalum cap layer provides protection to the sensor during manufacture and then is typically removed after performing annealing. The removal of the tantalum cap with a fluorine reactive ion etch leaves low volatility tantalum/fluorine byproducts. The present invention provides a method of using an argon/hydrogen reactive ion etch to remove the tantalum/fluorine byproducts. The resulting sensor has far less damage resulting from the presence of the fluorine byproducts.
    Type: Grant
    Filed: October 15, 2002
    Date of Patent: July 19, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Richard Hsiao, Wipul Pemsiri Jayasekara, Son Van Nguyen, Sue Zhang
  • Patent number: 6881497
    Abstract: A thermal spring magnetic medium is provided having first and second stacks providing two exchange coupled ferromagnetic layers having different Curie temperatures. The first stack has a high magneto-crystalline anisotropy, a relatively low saturation magnetization and a low Curie temperature. The second stack has a relatively low magneto-crystalline anisotropy, a high saturation magnetization and a high Curie temperature. Preferably the first stack includes an alloy of Fe—Pt or Co—Pt, and the second stack includes an allow of Co—Pt or Co—Pd. A disk drive system having the novel medium is also provided.
    Type: Grant
    Filed: November 14, 2003
    Date of Patent: April 19, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kevin Robert Coffey, Jan-Ulrich Thiele, Dieter Klaus Weller
  • Patent number: 6871998
    Abstract: The invention provides a method for accurately calibrating a vacuum thermogravimetric analyzer (VTGA). The invention solves the problem of calibrating a VTGA by using the actual magnetic transitions and associated transition temperatures, or Curie temperatures, Tc's, of a set of standards which can be used in-situ at the location of the sample holder obviating the difficulties associated with indirect methods of calibration. The invention encompasses a method of using a set of calibration standards comprised of a plurality of ferromagnetic slugs to provide a temperature calibration for a VTGA. The method permits accurate calibration through sufficiently numerous calibration points over a rather limited low-temperature range for determining vapor pressures of compounds. Through the use of these standards, highly accurate measurements can be made of the vapor pressures of critical hard disk drive compounds, such as lubricants, and corrosion inhibitors, that are crucial to competitive disk drive technology.
    Type: Grant
    Filed: August 1, 2003
    Date of Patent: March 29, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Malika Dothresa Carter, Michael Andrew Parker
  • Patent number: 6844144
    Abstract: A method of constructing an air bearing on a single slider used as a support for a magnetic recording head is described. A recessed surface of the air bearing is constructed by: applying a polymerization initiator (preferably azomonochlorsilane), forming a pattern in the initiator, forming a polymer brush, and ion milling. The application of the polymerization initiator may be from solution or by stamping.
    Type: Grant
    Filed: August 27, 2002
    Date of Patent: January 18, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Rainer Klaus Krause, Markus Schmidt, Stefan Seifried, Wolfgang Egert, Eva Urlaub, Ashok Lahiri
  • Patent number: 6842316
    Abstract: A magnetic spin valve sensor is provided which has antiparallel coupled end tabs to magnetically stabilize the free layer. The antiparallel coupled bias stabilization tabs include antiferromagnetic layers which are laterally recessed from the ends of the ferromagnetic bias layers. A disk drive is provided having the novel spin valve sensor as the read element.
    Type: Grant
    Filed: November 26, 2002
    Date of Patent: January 11, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 6835476
    Abstract: A magnetic recording medium for data storage uses a magnetic recording layer having at least two ferromagnetic films exchange coupled together antiferromagnetically across a nonferromagnetic spacer film. In this antiferromagnetically-coupled (AFC) recording layer the magnetic moments of the two ferromagnetic films are oriented antiparallel, and thus the net remanent magnetization-thickness product (Mrt) of the AFC recording layer is the difference in the Mrt values of the two ferromagnetic films. This reduction in Mrt is accomplished without a reduction in thermal stability of the recording medium. The lower ferromagnetic film in the AFC recording layer is a ferromagnetic CoCrFe alloy that does not require a nucleation layer between it and the Cr alloy underlayer. The medium with the CoCrFe alloy as the first or lower ferromagnetic film in the AFC recording layer has reduced intrinsic media noise.
    Type: Grant
    Filed: March 11, 2003
    Date of Patent: December 28, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hoa Van Do, Mary F. Doerner, Eric Edward Fullerton, David T. Margulies, Natacha F. Supper
  • Patent number: 6803119
    Abstract: This invention provides a disk which has an in-plane oriented magnetic recording layer on a glass, ceramic, or other nonmetal substrate and a method for making the disc. A thin layer of texturable NiP is sputtered on the substrate. This NiP layer is textured before the magnetic layer is deposited. The disk combines all the advantages of a glass or ceramic substrate along with the advantages of an oriented magnetic medium.
    Type: Grant
    Filed: September 13, 2001
    Date of Patent: October 12, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: David Thomas Margulies, Timothy Martin Reith, Hoa Do, Tim Minvielle, James A. Hagan
  • Patent number: 6797130
    Abstract: A magnetic disk is provided which comprises a nonmetallic glass or glass ceramic substrate having one or more under layers, a magnetic layer applied over the under layers, and a hard carbon layer applied over the magnetic layer. A plurality of bumps are formed on the magnetic disk by applying a beam from a near infrared wavelength laser to the surface of the carbon layer.
    Type: Grant
    Filed: June 27, 2003
    Date of Patent: September 28, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Iraj Kavosh, James Shuster, Andrew Ching Tam
  • Patent number: 6785099
    Abstract: A read head is provided having having ultrathin read gap layers with improved insulative properties between a magnetoresistive sensor and ferromagnetic shield layers. The read head comprises a magnetoresistive sensor with first and second shield cap layers made of high resistivity permeable magnetic material formed between the first and second ferromagnetic shields and the first and second insulative read gap layers, respectively. The shield cap layers made of Fe—Hf—Ox material, or alternatively, the Mn—Zn ferrite material provide highly resistive or insulating soft ferromagnetic layers which add to the electrically insulative read gap layers to provide increased electrical insulation of the spin valve sensor from the metallic ferromagnetic shields while not adding to the magnetic read gap of the read head.
    Type: Grant
    Filed: February 4, 2002
    Date of Patent: August 31, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Wen-Yaung Lee, Tsann Lin, Daniele Mauri
  • Patent number: 6785079
    Abstract: A method and apparatus for estimating the flyheight of an airbearing slider in a storage device. The slider floats on an airbearing over a rotating storage disk. The storage disk includes a washboard-sequence having washboard-sections each comprising surface profile variations having a different pitch. The pitches are selected from within a range of values likely to excite an airbearing resonance of the slider as the storage disk rotates at a rated storage disk velocity. For each of the washboard-sections, a maximum amplitude of flyheight modulation of the slider resulting from the slider floating over that washboard-section is measured. A determination is made of which washboard-section caused the largest measured flyheight modulation. The washboard-section having a pitch that provides an excitation frequency (when the disk is rotated at the rated storage disk velocity) that is closest to the actual airbearing resonance frequency of the slider will produce the largest flyheight modulation.
    Type: Grant
    Filed: March 16, 2001
    Date of Patent: August 31, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Hammond Brannon, Hal Hjalmar Ottesen, Gordon James Smith
  • Patent number: 6778360
    Abstract: A conductive path is provided to discharge electrostatic charges from a slider in a magnetic disk drive directly to the housing of the disk drive. In one embodiment conductive fibers electrically connect the slider with the housing. In another embodiment a cantilevered conductive finger electrically connects the slider with the housing. By providing a discharge path the accumulation of potentially damaging electrostatic charges is prevented.
    Type: Grant
    Filed: April 11, 2002
    Date of Patent: August 17, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Donald R. Gillis, Mike Suk
  • Patent number: 6775111
    Abstract: A trilayer seed layer structure is employed between a first read gap layer and a spin valve sensor for improving the magnetic and giant magnetoresistive properties and the thermal stability. In the spin valve sensor, the trilayer seed layer structure is located between a first read gap layer and a ferromagnetic free layer. The antiferromagnetic pinning layer is preferably nickel manganese (Ni—Mn). The trilayer seed layer structure includes a first seed layer that is a first metallic oxide, a second seed layer that is a second metallic oxide and a third seed layer that is a nonmagnetic metal. A preferred embodiment is a first seed layer of nickel oxide (NiO), a second seed layer of nickel manganese oxide (NiMnOx), and a third seed layer of copper (Cu).
    Type: Grant
    Filed: May 3, 2002
    Date of Patent: August 10, 2004
    Assignee: International Business Machines Corporation
    Inventors: Tsann Lin, Daniele Mauri