Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 6: Ultrafast magnetism I
MA 6.3: Vortrag
Montag, 12. März 2018, 10:00–10:15, EB 407
Ultrafast dynamics of Néel vector in aniferromagnetic thin films detected with optical pump probe spectroscopy — •Vladimir Grigorev1,2, Alexey Sapozhnik1,2, Stanislav Bodnar1, Martin Jordn1, and Jure Demsar1,2 — 1Institute of Physics, Johannes Gutenberg-University Mainz, Mainz, Germany — 2Graduate School of Excellence, Materials Science in Mainz (MAINZ), Mainz, Germany
Determination of the Néel vector in an antiferromagnetic (AFM) thin film is not trivial and usually requires large-scale facilities. Recently a novel method was demonstrated, utilizing the modulation aspect of the optical pump-probe technique [P. Saidl, et al., Nature Photonics 11, 91-97 (2017)]. We applied this method to determine the Néel vector in the c-axis oriented Mn2Au thin films. Analysis of angular dependence of the pump induced polarization rotation clearly suggests the Néel vector to be pointing along the <110> crystallographic direction, in agreement with recent experimental studies on bulk samples and theoretical calculations. Moreover, following the time evolution of the angular dependent polarization rotation, we were able to resolve the photoinduced rotation of the Néel vector and its recovery on the 100 picosecond timescale. The observed photoinduced rotation proceeds on the 5 ps timescale, which is in a good agreement with the characteristic time of strain induced expansion of the thin film. This suggests a strong coupling of the magnetic order to crystal lattice.