Bulletin of the American Physical Society
APS March Meeting 2021
Volume 66, Number 1
Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session V38: Spin Waves and Dynamics
3:00 PM–6:00 PM,
Thursday, March 18, 2021
Sponsoring Units: GMAG DMP FIAP
Chair: Peng Yan, University of Electronic Science and Technology of China
Abstract: V38.00009 : Optical spin-orbit torque and its application for spin-wave excitation*
5:00 PM–5:36 PM
In this work, we report optical spin-orbit torques in heavy metal/ferromagnet heterostructures . The strong spin-orbit coupling of heavy metals induces photo-excited carriers to be spin-polarized, and their transport from heavy metals to ferromagnets induces a torque on magnetization. These results resemble, in many ways, the electrically generated spin-orbit torque that also utilizes the strong spin-orbit coupling of heavy metals. We thus call the optically generated damping-like torque in heavy metal/ferromagnet heterostructures. as optical spin-orbit torque (OSOT).
Owing to its fast timescale, OSOT can be used to excite phase-coherent spin waves in the frequency range from GHz to THz [2,3]. Employing OSOT, we investigate the frequency, amplitude, and damping of spin waves. From the frequency analysis, we determine the spin wave stiffness. From the amplitude analysis, we show that FM acts as a cavity for spin waves. From the damping analysis, we observe a clear dependence on the FM thickness, which is attributed to the spin pumping effect of spin waves.
G.-M. Choi, J. H. Oh, D.-K. Lee, S.-W. Lee, K. W. Kim, M. Lim, B.-C. Min, K.-J. Lee, and H.-W. Lee, Nature Commun. Vol. 11, p. 1482 (2020).
G.-M. Choi, D.-K. Lee, K.-J. Lee, and H.-W. Lee, Phys. Rev. B Vol. 102, p. 014437 (2020).
G.-M. Choi, J. Magn. Magn. Mater. Vol. 516, p. 167335 (2020).
*Gyung-Min Choi acknowledges National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (NRF-2019R1C1C1009199).
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