MgO-C interlayer for grain size control in FePt-C media for heat assisted magnetic recording

Varaprasad, B. S. D. Ch. S.; Zhou, Bing; Mo, Tong; Laughlin, David E.; Zhu, Jian‐Gang

doi:10.1063/1.4973500

Cited by 9 publications

(2 citation statements)

References 10 publications

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“…If the initial anisotropy field is too strong, one can purposely heat the magnetic domains until they approach the Curie temperature and the spin polarization becomes weakly paramagnetic, allowing the magnetization to be altered. To date, much effort has also been focused on manipulating the anisotropy field in FePt alloys, nanoparticle arrays , and by varying capping or underlayers of the ferromagnetic films, − with state-of-the-art values for monolayer or ultrathin film spin-dependent Seebeck coefficients on the order of 10 3 μV/K . This would allow for a wide range of control over the anisotropic magnetic susceptibility that can be tailored to suit a variety of NFTs.…”

Section: Theoretical Methodsmentioning

confidence: 99%

Shaping and Storing Magnetic Data Using Pulsed Plasmonic Nanoheating and Spin-Transfer Torque

et al. 2019

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Spin transfer techniques have in recent years become attractive as an alternative to electronic-based devices for use in a wide range of magnetic devices such as spin valves for magnetic sensing, tunnel junctions and random access memories (MRAM; see the following refs: Chappert, C.; Fert, A.; Nguyen Van Dau, F. The emergence of spin electronics in data storage. Nat. Mater. 2007, 6, 813–823; Prejbeanu, I. L.; Kerekes, M.; Sousa, R. C.; Sibuet, H; Redon, O.; Dieny, B.; Nozières, J. P. Thermally assisted MRAM. J. Phys. Condens. Matter 2007, 19, 165218; Jain, S., Ranjan, A.; Roy, K.; Raghunathan, A. Computing in memory with spin-transfer torque magnetic RAM. IEEE Transactions on Very Large Scale Integration (VLSI) Systems 2018, 26, 470–483). Much effort has been placed on pursuing ultrathin media, which are not only ferromagnetic, but demonstrate a large spin-dependent Seebeck effect (SDSE) capable of generating the required spin currents for efficient nanoscale operation of these devices (see the following refs: Xiao, J. In Spintronics for Next Generation Innovative Devices; Katsuaki, S., Saitoh E., Eds.; Wiley: New York, 2015; pp 125–140; Ghiasi, T. S.; Ingla-Aynés, J.; Kaverzin, A. A; van Wees, B. J. Large proximity-induced spin lifetime anisotropy in transition-metal dichalcogenide/graphene heterostructures. Nano Lett. 2017, 17, 7528–7532; Comtesse, D.; Geisler, B.; Entel, P.; Kratzer, P.; Szunyogh, L. First-principles study of spin-dependent thermoelectric properties of half-metallic Heusler thin films between platinum leads. Phys. Rev. B 2014, 89, 094410). By generating very large temperature gradients on the order of 10 K/nm, the SDSE can produce a spin current that transfers the spin polarization of a magnetic domain (MD) along the gradient (∝ heat current). As spin accumulates in an adjacent domain, it is in turn able to induce a torque on its magnetic moments (see Choi, G-M.; Min, B-C.; Lee, K-J.; Cahill, D.G. Spin current generated by thermally driven ultrafast demagnetization. Nat. Commun. 2014, 5, 4334). As improvements in magnetic materials continue, we show by assuming reasonable enhancements of SDSE that a plasmonic near-field transducer (NFT) is able to create the very high temperature gradients in order to manipulate spin states in the heated region. This advancement allows the spin polarization to be adjusted without going above the material’s Curie limit. It also allows the spin-transfer torque (STT) to be applied over areas as small as a few tens of nm2 within the film, thus being able to write magnetic data more precisely without affecting the alignment of other nearby domains. This is crucial in order to have a high-fidelity and high-density bit writing process on the nanoscale. Herein we demonstrate via numerical analysis the ability to control the time dynamics of STT, which range from the ultrafast (pico) to the nanosecond regime, using only the heat currents produced by the NFT. This enables direct control over the alignment of the magnetization within the domains using plasmonic nanohea...

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Section: Theoretical Methodsmentioning

confidence: 99%

Shaping and Storing Magnetic Data Using Pulsed Plasmonic Nanoheating and Spin-Transfer Torque

et al. 2019

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“…We use media like that previously published on HAMR devices although optimization of the media itself or write pole was not part of this study [5,[38][39][40][41][42][43][44]. Additionally, the distance between the write pole and heated spot within the recording layer is limited so that the applied external magnetic field effectively adjusts the magnetization in the recording layer.…”

Section: Optical Behaviormentioning

confidence: 99%

Optical and thermal analysis of the light-heat conversion process employing an antenna-based hybrid plasmonic waveguide for HAMR

Abadía¹,

Bello²,

Zhong³

et al. 2018

Opt. Express

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Abstract:We investigate a tapered, hybrid plasmonic waveguide which has previously been proposed as an optically efficient near-field transducer (NFT), or component thereof, in several devices which aim to exploit nanofocused light. We numerically analyze how light is transported through the waveguide and ultimately focused via effective-mode coupling and taper optimization. Crucial dimensional parameters in this optimization process are identified that are not only necessary to achieve maximum optical throughput, but also optimum thermal performance with specific application towards heat-assisted magnetic recording (HAMR). It is shown that existing devices constructed on similar waveguides may benefit from a heat spreader to avoid deformation of the plasmonic element which we achieve with no cost to the optical efficiency. For HAMR, our design is able to surpass many industry requirements in regard to both optical and thermal efficiency using pertinent figure of merits like 8.5% optical efficiency. 503-510 (2015). 15. C. Peng, "Efficient excitation of a monopole optical transducer for near-field recording," J. Appl. Phys. 112(4), 043108 (2012). 16. X. He, L. Yang, and T. Yang, "Optical nanofocusing by tapering coupled photonic-plasmonic waveguides," Opt.Express 19

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Impact of carbon segregant on microstructure and magnetic properties of FePt-C nanogranular films on MgO (001) substrate

et al. 2019

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MgO-C interlayer for grain size control in FePt-C media for heat assisted magnetic recording

Cited by 9 publications

References 10 publications

Shaping and Storing Magnetic Data Using Pulsed Plasmonic Nanoheating and Spin-Transfer Torque

Shaping and Storing Magnetic Data Using Pulsed Plasmonic Nanoheating and Spin-Transfer Torque

Optical and thermal analysis of the light-heat conversion process employing an antenna-based hybrid plasmonic waveguide for HAMR

Impact of carbon segregant on microstructure and magnetic properties of FePt-C nanogranular films on MgO (001) substrate

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