Patents by Inventor Kumar Srinivasan

Kumar Srinivasan 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).

  • Publication number: 20260118451
    Abstract: Acoustically driven ferromagnetic resonance (ADFMR) sensor apparatuses may be tuned by the application of a tuning voltage. A tunable ADFMR sensor apparatus may include one or more tuning electrical contacts that are configured to adjust the output of the ADFMR magnetic field sensor, e.g., by applying a voltage to adjust a magnetic property of the multiferroic magnetic material of the ADFMR magnetic field sensor. Tuning may be performed in real time, or near-real time, based on an output of the ADFMR magnetic field sensor. In some cases tuning may include field zeroing and/or adjusting the range of field measurements.
    Type: Application
    Filed: March 20, 2024
    Publication date: April 30, 2026
    Inventors: Dominic LABANOWSKI, Kumar SRINIVASAN, Kenny GOTLIEB, Taylor WILLIAMS
  • Publication number: 20250020741
    Abstract: Apparatuses (e.g., system and devices, including sensors) and methods that may include single layered or multilayered stack-based acoustically driven ferromagnetic resonance (ADFMR) sensors that incorporate Fe—Ga—B materials (or in some cases Fe—Ga and C, Fe—Si and B, Fe—Si and C, Co—Fe and B, Co—Fe and C) as all or part of the thin-film magnetic element of the ADFMR sensors (e.g., the ferromagnetic film). These apparatuses and methods may have enhanced sensitivities when implemented as part of an ADFMR device. An Fe—Ga—B multilayered thin-film may be, e.g., between about 1 nm-1000 nm in total thickness.
    Type: Application
    Filed: July 15, 2024
    Publication date: January 16, 2025
    Inventors: Kumar SRINIVASAN, Vuk BRAJUSKOVIC, Dominic LABANOWSKI
  • Patent number: 11087791
    Abstract: A data storage drive includes a magnetic recording media comprising a ferroelectric layer between a bottom electrode layer and a top electrode layer. An applied voltage to the ferroelectric layer generates a strain that is transferred to a ferromagnetic recording layer formed proximate to the ferroelectric layer. The change in strain transferred to the recording layer changes the magnetic properties of the recording layer. A voltage can be selectively applied to all or part of the ferroelectric layer to place the ferromagnetic recording layer in a low coercivity state to assist in writing data. Voltage-assisted magnetic recording (VAMR) is provided based upon control of a magnetic recording media comprising a ferroelectric layer between a bottom electrode layer and a top electrode layer.
    Type: Grant
    Filed: May 5, 2020
    Date of Patent: August 10, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Alan Kalitsov, Kumar Srinivasan, Bhagwati Prasad
  • Patent number: 10783915
    Abstract: A method and system provide a magnetic recording media usable in a magnetic storage device. The magnetic recording media includes a substrate, at least one intermediate layer and a magnetic recording stack for storing magnetic data. The intermediate layer(s) include a majority phase having a first diffusion constant and a secondary phase having a second diffusion constant greater than the first diffusion constant. The magnetic recording stack residing on the intermediate layer such that the at least one intermediate layer is between the substrate and the magnetic recording stack.
    Type: Grant
    Filed: October 26, 2017
    Date of Patent: September 22, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kumar Srinivasan, Tuqiang Li, Mrugesh Desai
  • Patent number: 10276201
    Abstract: Magnetic media having dual phase MgO-X seed layers with both MgO grains and segregants are provided. One such magnetic medium includes a substrate, a heatsink layer on the substrate, a dual phase seed layer on the heatsink layer, where the dual phase seed layer comprises MgO and a segregant, where a concentration of the MgO is greater than 50 percent by volume in the dual phase seed layer, and a magnetic recording layer including FePt on the dual phase seed layer.
    Type: Grant
    Filed: February 22, 2016
    Date of Patent: April 30, 2019
    Assignee: WD MEDIA, LLC
    Inventors: Kumar Srinivasan, Tomoko Seki, Rui Zhang, Antony Ajan, Paul C. Dorsey
  • Patent number: 10109309
    Abstract: A heat-assisted magnetic recording (HAMR) medium includes a perpendicular magnetic recording layer (typically a chemically-ordered FePt alloy), a seed/thermal barrier layer (typically MgO) below the recording layer, and a heat-sink layer with anisotropic thermal conductivity below the seed/thermal barrier layer. The in-plane thermal conductivity of the heat-sink layer is greater than its out-of-plane thermal conductivity. The heat-sink layer may be selected from hexagonal boron nitride (h-BN), hexagonal graphite, and the 6H polytype of hexagonal silicon carbide (6H-SiC). If the heat-sink layer is h-BN, the h-BN layer is formed on a seed layer and has its c-axis oriented out-of-plane (substantially orthogonal to the surface of the medium substrate).
    Type: Grant
    Filed: September 1, 2017
    Date of Patent: October 23, 2018
    Assignee: Western Digital Technologies, Inc.
    Inventors: Pierre-Olivier Jubert, Kumar Srinivasan
  • Patent number: 10090014
    Abstract: A magnetic recording medium for heat assisted magnetic recording (HAMR) including in ascending vertical sequence: (i) a substrate; (ii) a first amorphous layer, a first seed layer, or a combination thereof; (iii) a heat sink layer comprising hexagonal boron-nitride grains; (iv) an optional second amorphous layer; (v) an optional second seed layer; (vi) a magnetic recording layer; (vii) an optional capping layer; and (viii) an optional overcoat layer; wherein: the magnetic recording medium has a substrate plane and a basal plane perpendicular to the substrate plane; the heat sink layer is anisotropic and has an a-axis thermal conductivity in the basal plane and a c-axis thermal conductivity in the substrate plane, wherein the a-axis thermal conductivity is greater than the c-axis thermal conductivity; and the hexagonal boron-nitride grains have an average size of at least about 10 nm in the substrate plane. Also, provided is a method of manufacturing the magnetic recording medium for HAMR.
    Type: Grant
    Filed: November 15, 2017
    Date of Patent: October 2, 2018
    Assignee: Western Digital Technologies, Inc.
    Inventors: Antony Ajan, Kumar Srinivasan, Ning Ye
  • Publication number: 20180047420
    Abstract: A method and system provide a magnetic recording media usable in a magnetic storage device. The magnetic recording media includes a substrate, at least one intermediate layer and a magnetic recording stack for storing magnetic data. The intermediate layer(s) include a majority phase having a first diffusion constant and a secondary phase having a second diffusion constant greater than the first diffusion constant. The magnetic recording stack residing on the intermediate layer such that the at least one intermediate layer is between the substrate and the magnetic recording stack.
    Type: Application
    Filed: October 26, 2017
    Publication date: February 15, 2018
    Inventors: Kumar Srinivasan, Tuqiang Li, Mrugesh Desai
  • Patent number: 9818442
    Abstract: A method and system provide a magnetic recording media usable in a magnetic storage device. The magnetic recording media includes a substrate, at least one intermediate layer and a magnetic recording stack for storing magnetic data. The intermediate layer(s) include a majority phase having a first diffusion constant and a secondary phase having a second diffusion constant greater than the first diffusion constant. The magnetic recording stack residing on the intermediate layer such that the at least one intermediate layer is between the substrate and the magnetic recording stack.
    Type: Grant
    Filed: December 1, 2014
    Date of Patent: November 14, 2017
    Assignee: WD MEDIA, LLC
    Inventors: Kumar Srinivasan, Tuqiang Li, Mrugesh Desai
  • Patent number: 9754618
    Abstract: A heat-assisted magnetic recording (HAMR) medium includes a substrate, a split heat-sink structure (SHSS) and a magnetic recording layer. The SHSS includes a first heat-sink layer disposed on the substrate, a heat-sink break layer (HSBL) disposed on the first heat-sink layer, and a second heat-sink layer disposed on the HSBL. The magnetic recording layer is disposed on the SHSS. The SHSS is configured to enable use of a reduced operating current of the laser while maintaining about the same write performance properties as a thermal barrier layer, heat-assisted magnetic recording (TBLHAMR) medium that includes a thermal barrier layer (TBL) and a heat-sink layer that is greater than about 20% thicker than the thickness of the SHSS. A HAMR data storage device that incorporates the HAMR medium within a HAMR disk, and a method for making the HAMR medium are also described.
    Type: Grant
    Filed: April 22, 2016
    Date of Patent: September 5, 2017
    Assignee: WD MEDIA, LLC
    Inventors: Kumar Srinivasan, Antony Ajan, George M. Chapline
  • Patent number: 9697859
    Abstract: A heat-assisted magnetic recording (HAMR) medium includes a substrate, a bi-layer, a heat-sink layer, and a magnetic-recording layer. The bi-layer includes a seed layer disposed on the substrate, and a thermal-transport-control layer (TTCL) disposed on seed layer. The heat-sink layer is disposed on the TTCL; and the magnetic-recording layer is disposed on the heat-sink layer. The bi-layer is configured to enable use of a 50% thinner heat-sink layer that allows use of a reduced operating current of a laser in HAMR write operations while maintaining about the same write performance parameters as a HAMR medium that includes a thermal-barrier layer (TBL) and twice as thick heat-sink layer. A HAMR data-storage device that incorporates the HAMR medium within a HAMR disk, and a method for making the HAMR medium are also described.
    Type: Grant
    Filed: April 1, 2016
    Date of Patent: July 4, 2017
    Assignee: WD MEDIA, LLC
    Inventors: Debashish Tripathy, Kumar Srinivasan, Antony Ajan
  • Patent number: 9685184
    Abstract: A recording medium having improved signal-to-noise ratio (SNR) capabilities includes a NiFeX-based magnetic seed layer over a soft magnetic underlayer, where X comprises an element that is soluble in and has a higher melting point than Ni. X may be selected from a group of elements, including ruthenium (Ru), which may facilitate growth of smaller grains and distributions in the corresponding magnetic recording layer(s).
    Type: Grant
    Filed: September 25, 2014
    Date of Patent: June 20, 2017
    Assignee: WD Media, LLC
    Inventors: Kumar Srinivasan, Tuqiang Li, Mrugesh Desai
  • Publication number: 20160155460
    Abstract: A method and system provide a magnetic recording media usable in a magnetic storage device. The magnetic recording media includes a substrate, at least one intermediate layer and a magnetic recording stack for storing magnetic data. The intermediate layer(s) include a majority phase having a first diffusion constant and a secondary phase having a second diffusion constant greater than the first diffusion constant. The magnetic recording stack residing on the intermediate layer such that the at least one intermediate layer is between the substrate and the magnetic recording stack.
    Type: Application
    Filed: December 1, 2014
    Publication date: June 2, 2016
    Inventors: KUMAR SRINIVASAN, TUQIANG LI, MRUGESH DESAI
  • Patent number: 9034492
    Abstract: Systems and methods for controlling the damping of magnetic media for heat assisted magnetic recording are provided. One such system includes a heat sink layer, a growth layer on the heat sink layer, a magnetic recording layer on the growth layer, where the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer, and a capping magnetic recording layer on the magnetic recording layer, the capping recording layer including a first material configured to increase a damping constant of the capping recording layer to a first preselected level.
    Type: Grant
    Filed: January 11, 2013
    Date of Patent: May 19, 2015
    Assignee: WD Media, LLC
    Inventors: Michael L. Mallary, Gerardo A. Bertero, Kumar Srinivasan
  • Patent number: 8758912
    Abstract: Embodiments of the present invention include a recording medium comprising: a hard magnetic recording layer and an interlayer disposed under the hard magnetic recording layer, wherein the interlayer comprises an upper layer of Ru-based alloy and a lower layer of RuCo or ReCo alloy. Generally for embodiments of the present invention, the lower layer of RuCo or ReCo alloy is formed over a seed layer using a low-pressure sputter process, and the upper layer of Ru-based alloy is formed over the lower layer using a high-pressure sputter process.
    Type: Grant
    Filed: September 16, 2011
    Date of Patent: June 24, 2014
    Assignee: WD Media, LLC
    Inventors: Kumar Srinivasan, B. Ramamurthy Acharya
  • Publication number: 20130071694
    Abstract: Embodiments of the present invention include a recording medium comprising: a hard magnetic recording layer and an interlayer disposed under the hard magnetic recording layer, wherein the interlayer comprises an upper layer of Ru-based alloy and a lower layer of RuCo or ReCo alloy. Generally for embodiments of the present invention, the lower layer of RuCo or ReCo alloy is formed over a seed layer using a low-pressure sputter process, and the upper layer of Ru-based alloy is formed over the lower layer using a high-pressure sputter process.
    Type: Application
    Filed: September 16, 2011
    Publication date: March 21, 2013
    Applicant: WD Media, Inc.
    Inventors: Kumar Srinivasan, B. Ramamurthy Acharya
  • Publication number: 20090226764
    Abstract: A magnetic recording medium and a method of making a magnetic recording medium are disclosed. The magnetic recording medium comprises an Iridium-Manganese based intermediate layer formed over a base structure and a magnetic recording layer formed over the Iridium-Manganese based intermediate layer.
    Type: Application
    Filed: April 17, 2009
    Publication date: September 10, 2009
    Applicant: AGENCY FOR SCIENCE, TECHNOLOGY & RESEARCH
    Inventors: Kumar Srinivasan, Rachid Sbiaa, S.N. Piramanayagam
  • Patent number: 6967196
    Abstract: In accordance with the present invention, there is provided a novel class of sulfonamide compounds. Compounds of the invention contain a core sulfonamide group. Variable moieties connected to the sulfur atom and nitrogen atom of the sulfonamide group include substituted or unsubstituted hydrocarbyl moieties, substituted or unsubstituted heterocycle moieties, polycyclic moieties, halogen, alkoxy, ether, ester, amide, sulfonyl, sulfonamidyl, sulfide, carbamate, and the like. Invention compounds are capable of a wide variety of uses. For example sulfonamide compounds can act to modulate production of amyloid ? protein and are useful in the prevention or treatment of a variety of diseases. Pharmaceutical compositions containing invention compounds are also provided. Such compositions have wide utility for the prevention or treatment of a variety of diseases.
    Type: Grant
    Filed: February 22, 2000
    Date of Patent: November 22, 2005
    Assignees: Bristol-Myers Squibb Company, Merck & Co. Inc.
    Inventors: David W. Smith, Benito Munoz, Kumar Srinivasan, Carl P. Bergstrom, Prasad V. Chaturvedula, Milind S. Deshpande, Daniel J. Keavy, Wai Yu Lau, Michael F. Parker, Charles P. Sloan, Owen B. Wallace, Henry Hui Wang
  • Patent number: 6638529
    Abstract: The present invention provides novel amide-based cationic lipids of the general structure: or a salt, or solvate, or enantiomers thereof wherein; (a) Y is a direct link or an alkylene of 1 to about 20 carbon atoms; (b) R1 is H or a lipophilic moiety; (c) R2, R3, and R4 are positively charged moieties, or at least one but not all of R2, R3, or R4 is a positive moiety and the remaining are independently selected from H, an alkyl moiety of 1 to about 6 carbon atoms, or a heterocyclic moiety of about 5 to about 10 carbon atoms; (d) n and p are independently selected integers from 0 to 8, such that the sum of n and o is from 1 to 16; (e) X− is an anion or polyanion and (f) m is an integer from 0 to a number equivalent to the positive charge(s) present on the lipid; provided that if Y is a direct link and the sum of n and p is 1 then one of either R3 or R4 must have an alkyl moiety of at least 10 carbon atoms.
    Type: Grant
    Filed: January 14, 2002
    Date of Patent: October 28, 2003
    Assignee: Genta Incorporated
    Inventors: David Aaron Schwartz, William J. Daily, Brian Patrick Dwyer, Kumar Srinivasan, Bob Dale Brown
  • Publication number: 20020156237
    Abstract: The present invention provides novel amide-based cationic lipids of the general structure: 1
    Type: Application
    Filed: January 14, 2002
    Publication date: October 24, 2002
    Applicant: Promega Biosciences, Inc.
    Inventors: David Aaron Schwartz, William J. Daily, Brian Patrick Dwyer, Kumar Srinivasan, Bob Dale Brown