Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 49: Terahertz dynamics

MA 49.2: Vortrag

Donnerstag, 15. März 2018, 15:15–15:30, EB 202

Antiferromagnetic resonance in Mn2Au driven by Néel spin orbit torque — •Nilabha Bhattacharjee, Stanislav Bodnar, Alexey Sapozhnik, Olena Gomonay, Martin Jourdan, and Jure Demsar — Johannes Gutenberg University, Mainz, 55099, Germany

Ultrafast spin dynamics in antiferromagnetic (AFM) materials has become a topic of immense interest due to its possible potential applications in spintronics. The AFM material Mn2Au, which is of huge prospect due to its high Néel temperature (~1600K) [1], strong spin-orbit coupling and high conductivity, requires a better understanding of its microscopic properties.

A comprehensive study of complex optical conductivity in thin c-axis grown Mn2Au films is presented in this work by means of time-domain THz spectroscopy.Thin (40 nm) Mn2Au films are grown by rf- sputtering on a 8 nm thick Ta buffer layer, deposited on a 500 micron thick R-cut sapphire substrate [2]. A damped antiferromagnetic resonance (AFMR) mode at 1THz (at room temperature) is observed in the conductivity data of Mn2Au by fitting with Drude-Lorentz model. A systematic study of temperature dependence of AFMR is been performed and a shift of the AFMR towards lower frequency is observed as the temperature varies from 5K to 450K. Here we also propose Néel spin orbit torque [3] driven mechanism of the in-plane AFMR mode in Mn2Au.

[1] S Khmelevskyi et al., App. Phys. Lett., 93, 162503 (2008). [2] M Jourdan et al., J. Phys. D: Appl. Phys., 48, 385001 (2015). [3] J. Železný et al., Phys. Rev. Lett. 113, 157201 (2014).