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).
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Publication number: 20240135969Abstract: Various apparatuses, systems, methods, and media are disclosed for heat-assisted magnetic recording (HAMR) that, in some examples, provide a HAMR medium with two soft underlayers (SULs) on opposing sides of a single heatsink layer. For example, a magnetic recording medium is provided that includes a lower SUL on a substrate. The lower SUL is configured and positioned within the medium to provide a first return path for magnetic flux from a magnetic recording head during a write operation. The medium also includes a heatsink layer on the lower SUL and an upper SUL on the heatsink layer. The upper SUL is configured and positioned within the medium to provide a second return path for magnetic flux from the magnetic recording head. A magnetic recording layer is provided on the upper SUL to store information during the write operation. Additional layers or films may be provided as well.Type: ApplicationFiled: July 24, 2023Publication date: April 25, 2024Inventors: Asif Bashir, Pierre-Olivier Jubert, Antony Ajan, Paul Christopher Dorsey
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Patent number: 11074934Abstract: HAMR media with a magnetic recording layer having a reduced Curie temperature and methods of fabricating the HAMR media are provided. One such HAMR medium includes a substrate, a heat sink layer on the substrate, an interlayer on the heat sink layer, and a multi-layer magnetic recording layer on the interlayer. In such case, the multi-layer magnetic recording layer includes a first magnetic recording layer including an alloy selected from FePtX and CoPtX, where X is a material selected from the group consisting of Cu, Ni, and combinations thereof, a second magnetic recording layer on the first magnetic recording layer and having at least one material different from the materials of the first magnetic recording layer, and a third magnetic recording layer on the second magnetic recording layer and having at least one material different from the materials of the first magnetic recording layer.Type: GrantFiled: September 25, 2015Date of Patent: July 27, 2021Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Hua Yuan, Antony Ajan, Oleg Krupin, B. Ramamurthy Acharya
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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: 10276199Abstract: High thermal gradient heatsinks for heat assisted magnetic recording media are provided. One example magnetic recording medium for heat assisted magnetic recording includes a substrate, a first seed layer on the substrate, a heatsink layer on the first seed layer and including Ru having a crystal texture of (11.0), a second seed layer on the heatsink layer, and a magnetic recording layer on the second seed layer. Methods for manufacturing such magnetic recording media are also disclosed.Type: GrantFiled: June 29, 2016Date of Patent: April 30, 2019Assignee: WD MEDIA, LLCInventors: Hoan Cong Ho, Tomoko Seki, Paul C. Dorsey, Antony Ajan
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Patent number: 10236026Abstract: Thermal barrier layers and seed layers for control of thermal and structural properties of 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 layer of SrTiO3 on the heat sink layer, an underlayer of MgO on the thermal barrier layer, and a magnetic recording layer on the underlayer. Another such HAMR medium includes a substrate, a heat sink layer on the substrate, a thermal barrier layer of an ABO3-type oxide on the heat sink layer, and a magnetic recording layer on the thermal barrier layer.Type: GrantFiled: November 6, 2015Date of Patent: March 19, 2019Assignee: WD MEDIA, LLCInventors: Rui Zhang, Tomoko Seki, Antony Ajan, Paul C. Dorsey
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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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Patent number: 9822441Abstract: A heat-assisted magnetic recording (HAMR) media stack is provided in which Iridium (Ir)-based materials may be utilized as a secondary underlayer instead of a Magnesium Oxide (MgO) underlayer utilized in conventional media stacks. Such Ir-based materials may include, e.g., pure Ir, Ir-based alloys, Ir-based compounds, as well as a granular Ir layer with segregants. The use of Ir or Ir-based materials as an underlayer provide advantages over the use of MgO as an underlayer. For example, DC sputtering can be utilized to deposit the layers of the media stack, where the deposition rate of Ir is considerably higher than that of MgO resulting in higher manufacturing production yields. Further still, less particles are generated during Ir-based layer deposition processes, and Ir-based underlayer can act as a better heat sink. Further still, the morphology and structure of a recording layer deposited on an Ir-based layer can be better controlled.Type: GrantFiled: March 31, 2015Date of Patent: November 21, 2017Assignee: WD Media, LLCInventors: Jiaxing Liu, Tomoko Seki, Antony Ajan, Rui Zhang
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Patent number: 9824711Abstract: A soft underlayer (SUL) and methods for making an SUL are provided, the SUL having characteristics that make it compatible with the high temperature requirements associated with heat-assisted magnetic recording (HAMR) media growth and writing, e.g., temperatures greater than 500° C. The SUL may have a high crystallization temperature of greater than 450° C. and a high Curie temperature greater than 300° C., for example. Additionally, the SUL can maintain a saturation magnetization value greater than, e.g., 9 kGauss, at such high temperatures, thereby having the ability to remain amorphous at temperatures up to, e.g., 650° C., and exhibiting a relatively flat integrated noise profile from approximately 300° C. to 650° C. Further still, a spacer layer material is chosen such that inter-diffusion does not occur at these high temperatures.Type: GrantFiled: June 25, 2014Date of Patent: November 21, 2017Assignee: WD Media, LLCInventors: Debashish Tripathy, Antony Ajan, Tomoko Seki, Gerardo A. Bertero
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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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Publication number: 20160293195Abstract: A heat-assisted magnetic recording (HAMR) media stack is provided in which Iridium (Ir)-based materials may be utilized as a secondary underlayer instead of a Magnesium Oxide (MgO) underlayer utilized in conventional media stacks. Such Ir-based materials may include, e.g., pure Ir, Ir-based alloys, Ir-based compounds, as well as a granular Ir layer with segregants. The use of Ir or Ir-based materials as an underlayer provide advantages over the use of MgO as an underlayer. For example, DC sputtering can be utilized to deposit the layers of the media stack, where the deposition rate of Ir is considerably higher than that of MgO resulting in higher manufacturing production yields. Further still, less particles are generated during Ir-based layer deposition processes, and Ir-based underlayer can act as a better heat sink. Further still, the morphology and structure of a recording layer deposited on an Ir-based layer can be better controlled.Type: ApplicationFiled: March 31, 2015Publication date: October 6, 2016Inventors: JIAXING LIU, TOMOKO SEKI, ANTONY AJAN, RUI ZHANG
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Patent number: 9449633Abstract: A recording medium having improved signal-to-noise ratio (SNR) capabilities and head-disk interface characteristics includes an etched smoothened underlayer, over which the recording layer is grown. One mechanism for increasing the SNR is by growing more columnar magnetic grain structures within the recording layer, which is facilitated by a smoother underlayer template.Type: GrantFiled: November 6, 2014Date of Patent: September 20, 2016Assignee: WD Media, LLCInventors: Shahid Pirzada, Tomoko Seki, B. Ramamurthy Acharya, Antony Ajan
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Patent number: 9406329Abstract: Segregants for magnetic recording layers and materials for intermediate layers underlying the magnetic recording layers are provided for improved heat assisted magnetic recording (HAMR) media. One such HAMR medium includes a substrate, a heat sink layer on the substrate, an underlayer on the heat sink layer, an intermediate layer of TiON, VON, CrON, TiOC, VOC, TiONC, and/or combinations thereof, on the underlayer, and a magnetic recording layer of FePt on the intermediate layer. The magnetic recording layer further includes three sublayers, each having a different segregant. The segregant of the first magnetic recording sublayer on the intermediate layer includes AgBN, AgCN, AgBNC, AgB2O3, AgMoO3, AgV2O5, B2O3, MoO3, V2O5, and/or combinations thereof.Type: GrantFiled: November 30, 2015Date of Patent: August 2, 2016Assignee: WD Media, LLCInventors: Hoan Cong Ho, Hua Yuan, Tomoko Seki, Antony Ajan, Paul C. Dorsey
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Publication number: 20160148634Abstract: Systems and methods for forming magnetic recording media with improved columnar growth for energy assisted magnetic recording are provided. In one such method, a first sub-layer of a magnetic layer is formed on a substrate, the magnetic layer including a magnetic material and a plurality of non-magnetic segregants, a top surface of the first sub-layer is etched to substantially remove the non-magnetic segregants accumulated on the top surface, and a second sub-layer of the magnetic layer is formed on the first sub-layer.Type: ApplicationFiled: February 2, 2016Publication date: May 26, 2016Inventors: ANTONY AJAN, ALEXANDER S. CHERNYSHOV, HUA YUAN, B. RAMAMURTHY ACHARYA
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Patent number: 9269480Abstract: Systems and methods for forming magnetic recording media with improved columnar growth for energy assisted magnetic recording are provided. In one such method, a first sub-layer of a magnetic layer is formed on a substrate, the magnetic layer including a magnetic material and a plurality of non-magnetic segregants, a top surface of the first sub-layer is etched to substantially remove the non-magnetic segregants accumulated on the top surface, and a second sub-layer of the magnetic layer is formed on the first sub-layer.Type: GrantFiled: March 30, 2012Date of Patent: February 23, 2016Assignee: WD Media, LLCInventors: Antony Ajan, Alexander Chernyshov, Hua Yuan, B. Ramamurthy Acharya
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Patent number: 9218850Abstract: A heat-assisted magnetic recording (HAMR) medium having improved signal-to-noise ratio capabilities includes a high-temperature exchange break layer (EBL) inserted between magnetic recording layers, where the high-temperature exchange break layer material is capable of maintaining its chemical properties at temperatures exceeding 300° C. The high-temperature EBL may include a non-metallic compound including at least one of an oxide, a carbide, and a nitride.Type: GrantFiled: December 23, 2014Date of Patent: December 22, 2015Assignee: WD Media, LLCInventors: Bincheng Wang, Alexander S. Chernyshov, Hua Yuan, Antony Ajan, B. Ramamurthy Acharya
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Patent number: 9177585Abstract: A method and system provide a magnetic recording media usable in a heat assisted magnetic recording (HAMR) disk drive. The magnetic recording media includes a magnetic recording layer, a crystalline underlayer, and a crystalline heat sink layer. The crystalline underlayer is between the crystalline heat sink layer and the magnetic recording layer. The magnetic recording layer stores magnetic data. The crystalline underlayer has a first crystal structure. The crystalline heat sink layer has a second crystal structure.Type: GrantFiled: December 4, 2013Date of Patent: November 3, 2015Assignee: WD Media, LLCInventors: Tomoko Seki, Antony Ajan, Hua Yuan, Alexander S. Chernyshov, Bincheng Wang, B. Ramamurthy Acharya
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Patent number: 9159350Abstract: A recording medium having improved signal-to-noise ratio (SNR) capabilities includes a cap layer over the recording layer, where the cap layer has a magnetic damping constant greater than 0.03, such as by using a FeHo cap layer. One mechanism for increasing the SNR is by reducing the switching field distribution. Such a medium is particularly useful in the context of heat-assisted magnetic recording (HAMR).Type: GrantFiled: July 2, 2014Date of Patent: October 13, 2015Assignee: WD Media, LLCInventors: Bincheng Wang, Antony Ajan, Michael L. Mallary
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Patent number: 8993134Abstract: 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: GrantFiled: June 29, 2012Date of Patent: March 31, 2015Assignee: Western Digital Technologies, Inc.Inventors: Bollapragada Varaprasad, Yukiko Takahashi, Kazuhiro Hono, Antony Ajan, Hua Yuan, Alexander S. Chernyshov
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Patent number: 8947987Abstract: Aspects of the present invention are directed to heat assisted magnetic recording (HAMR) media with a CoCrPtB based capping layer design that is capable of reducing switching field distribution and boosting signal-to-noise ratio of HAMR media. In one embodiment of the invention, a recording medium for heat assisted magnetic recording (HAMR) includes a substrate, a magnetic recording layer on the substrate, and a capping layer on and directly in contact with the magnetic recording layer. The capping layer includes CoCrPtB.Type: GrantFiled: July 1, 2013Date of Patent: February 3, 2015Assignee: WD Media, LLCInventors: Bincheng Wang, Alexander S. Chernyshov, Hua Yuan, Tomoko Seki, Antony Ajan, B. Ramamurthy Acharya