Patents by Inventor Antony Ajan

Antony Ajan 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: 8941950
    Abstract: Various embodiments provide for a heat assisted magnetic recording (HAMR) media comprising: a magnetic recording layer; a barrier layer disposed under the magnetic recording layer; a first underlayer disposed under the barrier layer; and an amorphous seedlayer disposed under the first underlayer. For some embodiments, the recording medium may comprise: a magnetic recording layer including FePt alloy, a CoPt alloy, or a FePd alloy; a barrier layer including MgO, TiC, TiN, CrN, TiCN, ?-WC, TaC, HfC, ZrC, VC, NbC, or NiO; a first underlayer including RuAl-oxide, NiAl, FeAl, AlMn, CuBe, or AlRe; or an amorphous seedlayer including a Cr—X alloy, where X comprises Al, B, C, Cu, Hf, Ho, Mn, Mo, Ni, Ta, Ti, V, W, or Ru.
    Type: Grant
    Filed: May 23, 2012
    Date of Patent: January 27, 2015
    Assignee: WD Media, LLC
    Inventors: Hua Yuan, Antony Ajan, Alexander S. Chernyshov, B. Ramamurthy Acharya
  • Publication number: 20140335376
    Abstract: A perpendicular magnetic recording medium, comprising: a substrate; a buffer layer deposited in a first orientation on top of the substrate; an underlayer deposited in a second orientation on top of the buffer layer, the underlayer comprising an electrically conductive oxide; and a magnetic recording layer deposited on top of the underlayer and having an axis of magnetic anisotropy substantially perpendicular to the surface thereof.
    Type: Application
    Filed: June 29, 2012
    Publication date: November 13, 2014
    Applicant: Western Digital Technologies, Inc.
    Inventors: BOLLAPRAGADA VALAPRASAD, Yukiko Takahashi, Kazuhiro Hono, Antony Ajan, Hua Yuan, Alexander S. Chernyshov
  • Patent number: 8867322
    Abstract: Systems and methods for providing thermal barrier bilayers for heat assisted magnetic recording (HAMR) media are provided. One such HAMR medium includes a substrate, a heat sink layer on the substrate, a thermal barrier bilayer on the heat sink layer, the bilayer comprising a first thermal barrier layer on the heat sink layer and an amorphous underlayer on the first thermal barrier layer, and a magnetic recording layer on the amorphous underlayer, wherein a thermal conductivity of the first thermal barrier layer is less than a thermal conductivity of the amorphous underlayer.
    Type: Grant
    Filed: July 1, 2013
    Date of Patent: October 21, 2014
    Assignee: WD Media, LLC
    Inventors: Alexander S. Chernyshov, Hua Yuan, Bincheng Wang, Tomoko Seki, Antony Ajan, B. Ramamurthy Acharya, Gerardo A. Bertero, David Treves
  • Patent number: 8787124
    Abstract: Systems and methods for extracting a Curie temperature distribution in a heat assisted magnetic recording medium are provided. One such method involves saturating a magnetic recording medium by causing a laser to direct light on the medium and causing a magnet adjacent to the medium to generate a magnetic field on the medium, causing the magnet to remove the magnetic field on the medium, writing to the medium by causing the laser to direct light on the medium, recording measurements of light reflected from the medium made by a light detector, converting the measurements of reflected light into measurements of remanent thermal magnetization, and extracting the Curie temperature distribution from the measurements of remanent thermal magnetization. One such system involves a processor coupled to a spindle, a magnet, a laser, and a light detector, where the processor is configured to perform this method.
    Type: Grant
    Filed: December 10, 2013
    Date of Patent: July 22, 2014
    Assignee: WD Media, LLC
    Inventors: Alexander S. Chernyshov, Thanh V. Le, David Treves, Antony Ajan, B. Ramamurthy Acharya
  • Patent number: 8787130
    Abstract: Systems and methods for providing heat assisted magnetic recording (HAMR) media configured to couple energy from a near field transducer (NFT) are provided. One such method includes providing a magnetic recording layer including an L10 ordered FePt or an L10 ordered CoPt, selecting a plurality of preselected parameters for a coupling layer, the preselected parameters including a material, a preselected deposition temperature, and a preselected thickness, and depositing the coupling layer directly on the magnetic recording layer using the preselected parameters such that the coupling layer has an extinction coefficient greater than 0.1.
    Type: Grant
    Filed: June 29, 2013
    Date of Patent: July 22, 2014
    Assignee: WD Media, LLC
    Inventors: Hua Yuan, Bogdan F. Valcu, Antony Ajan, B. Ramamurthy Acharya, Alexander S. Chernyshov, Paul C. Dorsey
  • Patent number: 8609263
    Abstract: Systems and methods for forming magnetic media with an underlayer are provided. One such method includes providing a non-magnetic substrate, forming a seed layer above the substrate, the seed layer including MgO, forming an underlayer on the seed layer, the underlayer including a material selected from the group consisting of Pd, Pt, W, Fe, V, Cu, and Ag, and forming a magnetic recording layer on the underlayer, the recording layer including FePt oxide.
    Type: Grant
    Filed: May 20, 2011
    Date of Patent: December 17, 2013
    Assignee: WD Media, LLC
    Inventors: Alexander Chernyshov, Hua Yuan, B. Ramamurthy Acharya, Antony Ajan
  • Patent number: 8605555
    Abstract: An energy assisted magnetic recording (EAMR) system includes a magnetic recording medium including a plurality of bi-layers and a magnetic recording layer on the plurality of bi-layers, a magnetic transducer configured to write information to the magnetic recording medium, and a light source positioned proximate the magnetic transducer and configured to heat the magnetic recording medium. Each of the plurality of bi-layers includes a heatsink layer and an amorphous under-layer on the heatsink layer.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: December 10, 2013
    Assignee: WD Media, LLC
    Inventors: Alexander S. Chernyshov, Hua Yuan, Bogdan Valcu, Antony Ajan, B. Ramamurthy Acharya
  • Publication number: 20130314815
    Abstract: Various embodiments provide for a heat assisted magnetic recording (HAMR) media comprising: a magnetic recording layer; a barrier layer disposed under the magnetic recording layer; a first underlayer disposed under the barrier layer; and an amorphous seedlayer disposed under the first underlayer. For some embodiments, the recording medium may comprise: a magnetic recording layer including FePt alloy, a CoPt alloy, or a FePd alloy; a barrier layer including MgO, TiC, TiN, CrN, TiCN, ?-WC, TaC, HfC, ZrC, VC, NbC, or NiO; a first underlayer including RuAl-oxide, NiAl, FeAl, AlMn, CuBe, or AlRe; or an amorphous seedlayer including a Cr—X alloy, where X comprises Al, B, C, Cu, Hf, Ho, Mn, Mo, Ni, Ta, Ti, V, W, or Ru.
    Type: Application
    Filed: May 23, 2012
    Publication date: November 28, 2013
    Applicant: WD MEDIA, INC.
    Inventors: Hua YUAN, Antony AJAN, Alexander S. CHERNYSHOV, B. Ramamurthy ACHARYA
  • Patent number: 7768731
    Abstract: A magnetic recording medium includes a first magnetic layer; and a second magnetic layer formed on the first magnetic layer. The first magnetic layer and the second magnetic layer make exchange coupling therebetween and also, have their magnetizing direction in anti-parallel to one another. A net residual area magnetization of the first magnetic layer and the second magnetic layer is expressed by the following formula: |Mr1×t1?Mr2×t2| where Mr1 and Mr2 denote respective residual magnetizations of the first magnetic layer and the second magnetic layer, and t1 and t2 denote respective film thicknesses of them; and the net area magnetization at a first temperature is larger than the net area magnetization at a second temperature lower than the first temperature.
    Type: Grant
    Filed: January 26, 2009
    Date of Patent: August 3, 2010
    Assignee: Showa Denko K.K.
    Inventors: Akihiro Inomata, Antony Ajan, Jun Taguchi, Koji Matsumoto, Wataru Yamagishi
  • Patent number: 7736769
    Abstract: A magnetic recording medium including a substrate having a surface, an orientation control layer disposed above the surface of the substrate, an underlayer disposed above the orientation control layer, and a recording layer having an hcp crystal structure and disposed on a surface of the underlayer. The recording layer is epitaxially grown on the surface of the underlayer to define a plurality of crystal grains, wherein the crystal grains have c-axes that are inclined in a plurality of random directions, but wherein each random direction defines an angle with respect to the surface of the substrate that is within a range that is greater than 0 degrees and less than or equal to 30 degrees. A magnetic storage apparatus including such a magnetic recording medium is also disclosed.
    Type: Grant
    Filed: February 3, 2006
    Date of Patent: June 15, 2010
    Assignee: Showa Denko K.K.
    Inventor: Antony Ajan
  • Publication number: 20090257147
    Abstract: A disclosed perpendicular magnetic recording medium includes a substrate; a soft magnetic underlayer disposed on the substrate and having no remanent magnetization; and a ferromagnetic recording layer disposed on the soft magnetic underlayer. The soft magnetic underlayer includes at least three soft magnetic layers laid one above the other with a non-magnetic intermediate layer interposed between every two adjacent soft magnetic layers. Among the (at least) three soft magnetic layers, at least one pair of soft magnetic layers form ferromagnetic coupling. Among the (at least) three soft magnetic layers, at least one pair of soft magnetic layers form antiferromagnetic coupling.
    Type: Application
    Filed: June 19, 2009
    Publication date: October 15, 2009
    Applicant: FUJITSU LIMITED
    Inventor: Antony Ajan
  • Patent number: 7566507
    Abstract: A magnetic recording medium is provided with an hcp Co alloy magnetic layer with the crystallographic c-axes tilted at an angle from a substrate surface and fixed relative to a recording direction. The tilt is induced by epitaxial growth of the hcp Co alloy on an obliquely evaporated nonmagnetic polycrystalline underlayer, so that the magnetic recording medium exhibits thermal stability and improved overwrite with a single pole-type head.
    Type: Grant
    Filed: September 7, 2005
    Date of Patent: July 28, 2009
    Assignee: Fujitsu Limited
    Inventors: E. Noel Abarra, Akihiro Inomata, Antony Ajan
  • Publication number: 20090135513
    Abstract: A magnetic recording medium includes a first magnetic layer; and a second magnetic layer formed on the first magnetic layer. The first magnetic layer and the second magnetic layer make exchange coupling therebetween and also, have their magnetizing direction in anti-parallel to one another. A net residual area magnetization of the first magnetic layer and the second magnetic layer is expressed by the following formula: |Mr1×t1?Mr2×t2| where Mr1 and Mr2 denote respective residual magnetizations of the first magnetic layer and the second magnetic layer, and t1 and t2 denote respective film thicknesses of them; and the net area magnetization at a first temperature is larger than the net area magnetization at a second temperature lower than the first temperature.
    Type: Application
    Filed: January 26, 2009
    Publication date: May 28, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Akihiro Inomata, Antony Ajan, Jun Taguchi, Koji Matsumoto, Wataru Yamagishi
  • Patent number: 7502188
    Abstract: A magnetic recording medium includes a first magnetic layer; and a second magnetic layer formed on the first magnetic layer. The first magnetic layer and the second magnetic layer make exchange coupling therebetween and also, have their magnetizing direction in anti-parallel to one another. A net residual area magnetization of the first magnetic layer and the second magnetic layer is expressed by the following formula: |Mr1×t1?Mr2×t2| where Mr1 and Mr2 denote respective residual magnetizations of the first magnetic layer and the second magnetic layer, and t1 and t2 denote respective film thicknesses of them; and the net area magnetization at a first temperature is larger than the net area magnetization at a second temperature lower than the first temperature.
    Type: Grant
    Filed: September 24, 2004
    Date of Patent: March 10, 2009
    Assignee: Fujitsu Limited
    Inventors: Akihiro Inomata, Antony Ajan, Jun Taguchi, Koji Matsumoto, Wataru Yamagishi
  • Patent number: 7470475
    Abstract: A magnetic recording medium includes a seed layer made of one of AlRu and AlV, a magnetic recording layer made of a CoCr alloy, and an underlayer made of the other of AlRu and AlV, where the underlayer is disposed between the seed layer and the magnetic recording layer.
    Type: Grant
    Filed: May 10, 2005
    Date of Patent: December 30, 2008
    Assignee: Fujitsu Limited
    Inventor: Antony Ajan
  • Publication number: 20080268293
    Abstract: According to an aspect of an embodiment, a magnetic recording medium includes a soft under layer, a seed layer containing an alloy, placed over the soft under layer, a ruthenium containing layer containing crystalline Ru, directly placed on the seed layer, and a recording layer placed over the ruthenium containing layer. The alloy contains metal atoms bonded to one another with a minimum distance of adjacent atoms. The difference between the minimum distance of the atoms in the alloy and that of the atoms in the crystalline Ru is 2% or less.
    Type: Application
    Filed: March 31, 2008
    Publication date: October 30, 2008
    Applicant: FUJITSU LIMITED
    Inventor: Antony Ajan
  • Publication number: 20080199734
    Abstract: The thickness of the spacer layer is set in such as way as to obtain the anti-parallel magnetic coupling between two amorphous ferromagnetic layers in the perpendicular medium. When the thickness of the spacer layer is changed, the exchange field shows an oscillatory behavior and the highest values of the exchange fields are obtained at various thicknesses and indicates an anti-parallel exchange between them. A conventional recording medium applies the smallest thickness (1st APS) among the thicknesses corresponding to the exchange field maximum. On the other hand, the present invention applies the second smallest thickness (2nd APS) to obtain larger tolerance of spacer layer thickness and improved writability and enhanced recording performance.
    Type: Application
    Filed: January 31, 2008
    Publication date: August 21, 2008
    Applicant: FUJITSU LIMITED
    Inventors: Antony Ajan, Toshio Sugimoto
  • Publication number: 20080100962
    Abstract: A crystallized ferromagnetic layer containing Fe, Co and/or Ni, formed as a polycrystalline ferromagnetic layer is used as a part of the anti parallel soft under layer (APS-SUL) structure in perpendicular media to reduce the thickness of the intermediate layer. The soft under layer structure consists of a non-magnetic spacer layer, whose thickness is adjusted to form an effective anti-parallel coupling between the two ferromagnetic layers. The magnetic coupling is formed in anti-parallel directions between a lower layer made up of an amorphous ferromagnetic layer and an upper layer made up of an amorphous ferromagnetic layer and the polycrystalline ferromagnetic layer. The effective magnetization of the soft under layers at remanence is zero. The preferred thickness of the polycrystalline ferromagnetic layer is 1 nm to 20 nm. An intermediate layer, such as Ru, is formed directly on the magnetic polycrystalline soft under layer and has a thickness of about 10 nm to 20 nm.
    Type: Application
    Filed: August 31, 2007
    Publication date: May 1, 2008
    Applicant: FUJITSU LIMITED
    Inventor: Antony AJAN
  • Patent number: 7354665
    Abstract: A magnetic recording medium is provided with a substrate, a recording magnetic layer made of a CoCr alloy and having a (11 20) crystallographic texture, and an underlayer, made of an AlV or AlRuV alloy, disposed between the substrate and the magnetic layer.
    Type: Grant
    Filed: February 23, 2005
    Date of Patent: April 8, 2008
    Assignee: Fujitsu Limited
    Inventors: Antony Ajan, E. Noel Abarra
  • Publication number: 20070231609
    Abstract: A perpendicular magnetic recording medium is disclosed that includes a substrate, and a recording layer formed on the substrate, the recording layer having a magnetic easy axis substantially perpendicular to the surface of the substrate and including three or more magnetic layers containing a Co alloy having a hcp structure. The two of the magnetic layers included in the recording layer form an anti-ferromagnetic exchange coupling structure. The two magnetic layers are anti-ferromagnetically exchange coupled via a non-magnetic coupling layer situated therebetween. The magnetizations of the two magnetic layers are anti-parallel to each other at a remanent magnetization state.
    Type: Application
    Filed: August 18, 2006
    Publication date: October 4, 2007
    Applicant: FUJITSU LIMITED
    Inventors: Antony Ajan, Toshio Sugimoto, Ryo Kurita