Generation and amplification of propagating spin waves by spin-orbit torque
Final Report Abstract
The main goal of this project was to achieve efficient excitation of coherent spin waves and their true spatially extended amplification by the spin-orbit torque (SOT) in nano-structured systems based on conducting and insulating magnetic materials. In the course of the project implementation, we were able to identify the main limiting physical mechanisms in SOT-driven nano-systems and develop approaches to overcome them. In particular, we have proposed and experimentally tested a simple and robust method based on the use of perpendicular magnetic anisotropy, which allows one to suppress the detrimental nonlinear scattering effects and achieve complete compensation of the natural magnetic damping by SOT over extended spatial regions. We have shown that this approach makes it possible to achieve efficient excitation of coherent magnetization dynamics without limiting the geometry or the efficiency of SOT-driven nano-devices. We have also experimentally demonstrated that this approach enables a true amplification of spin waves resulting in an exponential increase of their intensity during propagation in nano-waveguides. These findings open new avenues for the field of nano-magnonics by demonstrating a simple and energy-efficient approach for on-chip generation and amplification of propagating spin waves, which can be used in most of nanoscale magnonic devices. The possibility to directly amplify propagating spin waves enables implementation of complex magnonic nano-circuits that do not require energy-consuming conversion of spin waves into electronic signals for compensation of propagation losses, and is expected to significantly advance practical realization of magnon-based computing platforms.
Publications
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Route toward high-speed nano-magnonics. 2017 IEEE International Magnetics Conference (INTERMAG) (2017, 4), 1-1. American Geophysical Union (AGU).
Divinskiy, B.; Demidov, V.E.; Demokritov, S.O. & Urazhdin, S.
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Effects of Spin-Orbit Torque on the Ferromagnetic and Exchange Spin-Wave Modes in Ferrimagnetic Co - Gd Alloy. Physical Review Applied, 14(4).
Divinskiy, Boris; Chen, Guanxiong; Urazhdin, Sergei; Demokritov, Sergej O. & Demidov, Vladislav E.
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Spin–orbit-torque magnonics. Journal of Applied Physics, 127(17).
Demidov, V. E.; Urazhdin, S.; Anane, A.; Cros, V. & Demokritov, S. O.
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Sub-micrometer near-field focusing of spin waves in ultrathin YIG films. Applied Physics Letters, 116(6).
Divinskiy, B.; Thiery, N.; Vila, L.; Klein, O.; Beaulieu, N.; Ben, Youssef J.; Demokritov, S. O. & Demidov, V. E.
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The 2021 Magnonics Roadmap. Journal of Physics: Condensed Matter, 33(41), 413001.
Barman, Anjan; Gubbiotti, Gianluca; Ladak, S.; Adeyeye, A. O.; Krawczyk, M.; Gräfe, J.; Adelmann, C.; Cotofana, S.; Naeemi, A.; Vasyuchka, V. I.; Hillebrands, B.; Nikitov, S. A.; Yu, H.; Grundler, D.; Sadovnikov, A. V.; Grachev, A. A.; Sheshukova, S. E.; Duquesne, J.-Y.; Marangolo, M.; ... & Winklhofer, M.
