Patents by Inventor Tomoko SEKI
Tomoko SEKI 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: 20250124951Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a magnetic recording layer on a MgO—TiO (MTO) underlayer, where the MTO underlayer is formed using pulsed DC sputtering and has less than 50 mol % of TiO. By providing an MTO layer with less than 50 mol % of TiO, smaller grain sizes may be achieved in the magnetic recording layer, providing for higher areal densities. In some embodiments, a second MTO underlayer is provided, which is formed using non-pulsed DC sputtering and has 50 mol % of TiO. That is, a dual-layer MTO underlayer may be provided with, e.g., an MgO-30TiO layer atop an MgO-50TiO layer.Type: ApplicationFiled: October 12, 2023Publication date: April 17, 2025Inventors: Hoan Cong Ho, Paul Christopher Dorsey, Tomoko Seki, Pierre-Olivier Jubert
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Patent number: 12272392Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium. The HAMR medium includes a substrate, a heat sink layer on the substrate, and a plurality of magnetic recording layers on the heat sink layer. The plurality of magnetic recording layers includes a first magnetic layer and a second magnetic layer disposed on the first magnetic layer. The second magnetic layer includes FePt—Ag—Cu—X, wherein X is a segregant comprising BN. The HAMR medium can use BN-based segregants to improve a thermal gradient of the HAMR medium for better areal density capability (ADC) and enable the use of a MgO underlayer with reduced thickness.Type: GrantFiled: August 25, 2022Date of Patent: April 8, 2025Assignee: Western Digital Technologies, Inc.Inventors: Hoan Cong Ho, Tomoko Seki, Paul Christopher Dorsey
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Publication number: 20240071416Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium. The HAMR medium includes a substrate, a heat sink layer on the substrate, and a plurality of magnetic recording layers on the heat sink layer. The plurality of magnetic recording layers includes a first magnetic layer and a second magnetic layer disposed on the first magnetic layer. The second magnetic layer includes FePt—Ag—Cu—X, wherein X is a segregant comprising BN. The HAMR medium can use BN-based segregants to improve a thermal gradient of the HAMR medium for better areal density capability (ADC) and enable the use of a MgO underlayer with reduced thickness.Type: ApplicationFiled: August 25, 2022Publication date: February 29, 2024Inventors: Hoan Cong Ho, Tomoko Seki, Paul Christopher Dorsey
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Publication number: 20240055019Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a magnetic recording layer on a magnesium oxide-titanium oxide (MTO) underlayer, where the MTO underlayer includes an additive material that chemically bonds with titanium. In some examples, the additive material includes iron-oxide, iron, carbon, or various aluminum oxides. By providing the additive material to the MTO that chemically bonds with the titanium of the MTO, diffusion of titanium from the MTO underlayer into the magnetic recording layer is mitigated to provide an improved recording layer that achieves improved areal densities. In some embodiments, an additional magnesium oxide-nitrogen underlayer is also provided, which may include more of the additive material.Type: ApplicationFiled: August 11, 2022Publication date: February 15, 2024Inventors: Hoan Cong Ho, Hua Yuan, Tomoko Seki, Paul Christopher Dorsey
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Patent number: 11900978Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a magnetic recording layer on a magnesium oxide-titanium oxide (MTO) underlayer, where the MTO underlayer includes an additive material that chemically bonds with titanium. In some examples, the additive material includes iron-oxide, iron, carbon, or various aluminum oxides. By providing the additive material to the MTO that chemically bonds with the titanium of the MTO, diffusion of titanium from the MTO underlayer into the magnetic recording layer is mitigated to provide an improved recording layer that achieves improved areal densities. In some embodiments, an additional magnesium oxide-nitrogen underlayer is also provided, which may include more of the additive material.Type: GrantFiled: August 11, 2022Date of Patent: February 13, 2024Assignee: Western Digital Technologies, Inc.Inventors: Hoan Cong Ho, Hua Yuan, Tomoko Seki, Paul Christopher Dorsey
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Publication number: 20230005503Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a magnesium (Mg) trapping layer that is configured to mitigate Mg migration in the HAMR medium so as to prevent near field transducer (NFT) damage caused by dissociated Mg reacting with a compound used in the NFT. In one example, the HAMR medium can include a substrate, a seed layer on the substrate and including MgO, a magnetic recording layer on the seed layer, and a Mg trapping layer on the substrate and configured to mitigate Mg migration from the seed layer to a surface of the HAMR medium above the magnetic recording layer.Type: ApplicationFiled: July 1, 2021Publication date: January 5, 2023Inventors: Takashi Iwanami, Kouji Matsuda, Junguo Xu, Kenji Tasaka, Hoan Cong Ho, Tomoko Seki, Paul Christopher Dorsey, Masayoshi Shimokoshi
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Patent number: 11521648Abstract: A heat-assisted magnetic recording (HAMR) medium has a multilayered underlayer between the heat-sink layer and the recording layer. One embodiment of the underlayer is a multilayer of a thermal barrier layer consisting essentially of MgO and TiO, and a seed layer containing MgO and nitrogen (N) directly on the thermal barrier layer, with the recording layer on and in contact with the seed layer. The interface between the thermal barrier layer and the seed layer contains Ti and N, some of which may be present as TiN to act as a diffusion barrier to prevent diffusion of the Ti into the recording layer. The Ti-containing thermal barrier layer has a higher thermal resistivity than the conventional MgO thermal barrier/seed layer and thus allows for reduced laser power to the recording layer while still achieving a high thermal gradient at the recording layer.Type: GrantFiled: February 9, 2021Date of Patent: December 6, 2022Assignee: Western Digital Technologies, Inc.Inventors: Hoan Cong Ho, Paul Christopher Dorsey, Tomoko Seki
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Publication number: 20220139422Abstract: A heat-assisted magnetic recording (HAMR) medium has a multilayered underlayer between the heat-sink layer and the recording layer. One embodiment of the underlayer is a multilayer of a thermal barrier layer consisting essentially of MgO and TiO, and a seed layer containing MgO and nitrogen (N) directly on the thermal barrier layer, with the recording layer on and in contact with the seed layer. The interface between the thermal barrier layer and the seed layer contains Ti and N, some of which may be present as TiN to act as a diffusion barrier to prevent diffusion of the Ti into the recording layer. The Ti-containing thermal barrier layer has a higher thermal resistivity than the conventional MgO thermal barrier/seed layer and thus allows for reduced laser power to the recording layer while still achieving a high thermal gradient at the recording layer.Type: ApplicationFiled: February 9, 2021Publication date: May 5, 2022Inventors: Hoan Cong Ho, Paul Christopher Dorsey, Tomoko Seki
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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: 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: 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: 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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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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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: 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
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Patent number: 8867322Abstract: 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: GrantFiled: July 1, 2013Date of Patent: October 21, 2014Assignee: WD Media, LLCInventors: Alexander S. Chernyshov, Hua Yuan, Bincheng Wang, Tomoko Seki, Antony Ajan, B. Ramamurthy Acharya, Gerardo A. Bertero, David Treves
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Patent number: 8431257Abstract: A perpendicular magnetic recording medium is used for information recording of a perpendicular magnetic recording type. The perpendicular magnetic recording medium includes a substrate, a soft magnetic layer, an underlayer, and a magnetic layer having a multilayered structure including a plurality of magnetic layers. The soft magnetic layer, the underlayer, and the magnetic layer are formed on the substrate. At least one of the magnetic layers includes CoPt magnetic grains containing oxide. The oxide includes at least one material selected from the group consisting of SiO2, TiO2, Cr2O3, Ta2O5, WO3, CoO, and Co3O4.Type: GrantFiled: March 29, 2010Date of Patent: April 30, 2013Assignee: WD Media (Singapore) PTE. Ltd.Inventors: Kong Kim, Hi Shin, Tomoko Seki, Satoshi Ishii