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).
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Publication number: 20260118451Abstract: 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: ApplicationFiled: March 20, 2024Publication date: April 30, 2026Inventors: Dominic LABANOWSKI, Kumar SRINIVASAN, Kenny GOTLIEB, Taylor WILLIAMS
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Publication number: 20250020741Abstract: 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: ApplicationFiled: July 15, 2024Publication date: January 16, 2025Inventors: Kumar SRINIVASAN, Vuk BRAJUSKOVIC, Dominic LABANOWSKI
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Patent number: 11087791Abstract: 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: GrantFiled: May 5, 2020Date of Patent: August 10, 2021Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Alan Kalitsov, Kumar Srinivasan, Bhagwati Prasad
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Patent number: 10783915Abstract: 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: GrantFiled: October 26, 2017Date of Patent: September 22, 2020Assignee: Western Digital Technologies, Inc.Inventors: Kumar Srinivasan, Tuqiang Li, Mrugesh Desai
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Patent number: 10276201Abstract: 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: GrantFiled: February 22, 2016Date of Patent: April 30, 2019Assignee: WD MEDIA, LLCInventors: Kumar Srinivasan, Tomoko Seki, Rui Zhang, Antony Ajan, Paul C. Dorsey
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Patent number: 10109309Abstract: 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: GrantFiled: September 1, 2017Date of Patent: October 23, 2018Assignee: Western Digital Technologies, Inc.Inventors: Pierre-Olivier Jubert, Kumar Srinivasan
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Patent number: 10090014Abstract: 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: GrantFiled: November 15, 2017Date of Patent: October 2, 2018Assignee: Western Digital Technologies, Inc.Inventors: Antony Ajan, Kumar Srinivasan, Ning Ye
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Publication number: 20180047420Abstract: 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: ApplicationFiled: October 26, 2017Publication date: February 15, 2018Inventors: Kumar Srinivasan, Tuqiang Li, Mrugesh Desai
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Patent number: 9818442Abstract: 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: GrantFiled: December 1, 2014Date of Patent: November 14, 2017Assignee: WD MEDIA, LLCInventors: Kumar Srinivasan, Tuqiang Li, Mrugesh Desai
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Patent number: 9754618Abstract: 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: GrantFiled: April 22, 2016Date of Patent: September 5, 2017Assignee: WD MEDIA, LLCInventors: Kumar Srinivasan, Antony Ajan, George M. Chapline
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Patent number: 9697859Abstract: 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: GrantFiled: April 1, 2016Date of Patent: July 4, 2017Assignee: WD MEDIA, LLCInventors: Debashish Tripathy, Kumar Srinivasan, Antony Ajan
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Patent number: 9685184Abstract: 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: GrantFiled: September 25, 2014Date of Patent: June 20, 2017Assignee: WD Media, LLCInventors: Kumar Srinivasan, Tuqiang Li, Mrugesh Desai
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Publication number: 20160155460Abstract: 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: ApplicationFiled: December 1, 2014Publication date: June 2, 2016Inventors: KUMAR SRINIVASAN, TUQIANG LI, MRUGESH DESAI
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Patent number: 9034492Abstract: 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: GrantFiled: January 11, 2013Date of Patent: May 19, 2015Assignee: WD Media, LLCInventors: Michael L. Mallary, Gerardo A. Bertero, Kumar Srinivasan
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Patent number: 8758912Abstract: 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: GrantFiled: September 16, 2011Date of Patent: June 24, 2014Assignee: WD Media, LLCInventors: Kumar Srinivasan, B. Ramamurthy Acharya
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Publication number: 20130071694Abstract: 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: ApplicationFiled: September 16, 2011Publication date: March 21, 2013Applicant: WD Media, Inc.Inventors: Kumar Srinivasan, B. Ramamurthy Acharya
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Publication number: 20090226764Abstract: 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: ApplicationFiled: April 17, 2009Publication date: September 10, 2009Applicant: AGENCY FOR SCIENCE, TECHNOLOGY & RESEARCHInventors: Kumar Srinivasan, Rachid Sbiaa, S.N. Piramanayagam
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Patent number: 6967196Abstract: 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: GrantFiled: February 22, 2000Date of Patent: November 22, 2005Assignees: 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
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Patent number: 6638529Abstract: 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: GrantFiled: January 14, 2002Date of Patent: October 28, 2003Assignee: Genta IncorporatedInventors: David Aaron Schwartz, William J. Daily, Brian Patrick Dwyer, Kumar Srinivasan, Bob Dale Brown
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Publication number: 20020156237Abstract: The present invention provides novel amide-based cationic lipids of the general structure: 1Type: ApplicationFiled: January 14, 2002Publication date: October 24, 2002Applicant: Promega Biosciences, Inc.Inventors: David Aaron Schwartz, William J. Daily, Brian Patrick Dwyer, Kumar Srinivasan, Bob Dale Brown