Patents by Inventor David T. Margulies

David T. Margulies has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9127365
    Abstract: Methods of fabricating perpendicular magnetic recording media are disclosed. The multilayer structures of the perpendicular magnetic recording media are fabricated by varying the sputtering conditions (i.e., pressure, sputtering gas, etc) in a single sputtering module so that multiple sputtering modules are not needed to form the multilayer structures. These fabrication methods allow sputtering tools with a limited number of chambers, which were designed for the manufacture of longitudinal media, to be used to efficiently produce perpendicular media architectures which heretofore required a large number of sputtering modules. It is further shown that media structures involving a geometric weak-link architecture are suited for these fabrication techniques.
    Type: Grant
    Filed: February 16, 2008
    Date of Patent: September 8, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Andreas K. Berger, Yoshihiro Ikeda, Byron H. Lengsfield, III, David T. Margulies, Ernesto E. Marinero
  • Publication number: 20090205948
    Abstract: Methods of fabricating perpendicular magnetic recording media are disclosed. The multilayer structures of the perpendicular magnetic recording media are fabricated by varying the sputtering conditions (i.e., pressure, sputtering gas, etc) in a single sputtering module so that multiple sputtering modules are not needed to form the multilayer structures. These fabrication methods allow sputtering tools with a limited number of chambers, which were designed for the manufacture of longitudinal media, to be used to efficiently produce perpendicular media architectures which heretofore required a large number of sputtering modules. It is further shown that media structures involving a geometric weak-link architecture are suited for these fabrication techniques.
    Type: Application
    Filed: February 16, 2008
    Publication date: August 20, 2009
    Inventors: Andreas K. Berger, Yoshihiro Ikeda, Byron H. Lengsfield, III, David T. Margulies, Ernesto E. Marinero
  • Patent number: 7529065
    Abstract: The invention uses an upper and lower magnetic layer of a laminated magnetic layer structure that includes an AF spacer layer that results in weak antiferromagnetic coupling of the magnetic layers that is insufficient to cause either of the layers to switch so that the magnetic orientations of the two ferromagnetic layers remain parallel. An advantage of the invention is that the AF-coupling tends to anti-correlate the noise in the two layers. The weak AF coupling according to the invention is believed to act at the transition boundaries in the media to cause some of the noise domains to be oriented antiparallel and the noise to be less correlated than would be the case without the AF coupling and thereby to achieve improved SNR.
    Type: Grant
    Filed: May 19, 2005
    Date of Patent: May 5, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Eric Edward Fullerton, Olav Hellwig, Byron Hassberg Lengsfield, III, David T. Margulies
  • Patent number: 6989952
    Abstract: A magnetic recording disk drive has an inductive write head and a heater to record data in laminated media on the recording disk. The laminated media, with at least two ferromagnetic layers separated by a nonmagnetic spacer layer, improves SNR. Each of the ferromagnetic layers can be formed of a material having an intrinsic coercivity capable of being written by a conventional inductive write head, but because of the desired lamination to increase SNR, the ferromagnetic layer farthest from the write head is exposed to a magnetic field less than its intrinsic coercivity and thus can not be written. To write to the laminated media, heat is directed to the lower ferromagnetic layer to reduce its intrinsic coercivity below the magnetic field to which it is exposed.
    Type: Grant
    Filed: July 15, 2003
    Date of Patent: January 24, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: David T. Margulies, Andreas Moser, Hal J. Rosen, Jan-Ulrich Thiele
  • Patent number: 6963461
    Abstract: A magnetic recording disk drive has an inductive write head and a heater to record data in laminated media on the recording disk. The laminated media, with at least two ferromagnetic layers separated by a nonmagnetic spacer layer, improves SNR. Each of the ferromagnetic layers can be formed of a material having an intrinsic coercivity capable of being written by a conventional inductive write head, but because of the desired lamination to increase SNR, the ferromagnetic layer farthest from the write head is exposed to a magnetic field less than its intrinsic coercivity and thus can not be written. To write to the laminated media, heat is directed to the lower ferromagnetic layer to reduce its intrinsic coercivity below the magnetic field to which it is exposed.
    Type: Grant
    Filed: July 15, 2003
    Date of Patent: November 8, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: David T. Margulies, Andreas Moser, Hal J. Rosen, Jan-Ulrich Thiele
  • 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
  • Publication number: 20040180173
    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: Application
    Filed: March 11, 2003
    Publication date: September 16, 2004
    Inventors: Hoa Van Do, Mary F. Doerner, Eric Edward Fullerton, David T. Margulies, Natacha F. Supper
  • Patent number: 6567236
    Abstract: An antiferromagnetically coupled layer structure for magnetic recording wherein the top ferromagnetic structure is a bilayer structure including a relatively thin first sublayer of ferromagnetic material in contact with the coupling/spacer layer. The first sublayer has a higher magnetic moment than the second sublayer. The layer structure of the invention results improved manufacturability and improved performance. A preferred embodiment of a layer structure according to the invention includes: a bottom ferromagnetic layer preferably of CoCr; an antiferromagnetic coupling/spacer layer preferably of Ru; and a top ferromagnetic structure including a thin first sublayer of material preferably of CoCr, CoCrB or CoPtCrB, and a thicker second sublayer of material preferably of CoPtCrB with a lower moment than the first sublayer.
    Type: Grant
    Filed: November 9, 2001
    Date of Patent: May 20, 2003
    Assignee: International Business Machnes Corporation
    Inventors: Mary Frances Doerner, Eric E. Fullerton, David T. Margulies, Kai Tang
  • Patent number: RE38474
    Abstract: 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: Grant
    Filed: August 27, 2002
    Date of Patent: March 23, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: David T. Margulies, Ernesto E. Marinero, Hal J. Rosen, Brian R. York, Kurt A. Rubin