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MA: Fachverband Magnetismus
MA 44: Magnetic imaging (Experimental techniques)
MA 44.2: Vortrag
Donnerstag, 4. April 2019, 09:45–10:00, H53
Nanoscale imaging of ultrafast spin dynamics using high-harmonic radiation — •Sergey Zayko1, Ofer Kfir1, Michael Heigl2, Michael Lohmann1, Murat Sivis1, Manfred Albrecht2, and Claus Ropers1 — 1IV Physical Institute, University of Göttingen — 2Institute of Physics, University of Augsburg
Sources of ultrashort pulses at the extreme-UV and soft-X-rays provide for an ultrafast probe of magnetic textures and topological spin arrangements, such as domain patterns and skyrmions. However, despite a widespread application of high harmonic spectroscopy over the past decade, magnetic imaging using high harmonics has only recently been demonstrated [1]. Here, we report the first demonstration of nanoscale real-space imaging of ultrafast spin dynamics using circularly-polarized high-harmonic radiation. By measuring transient x-ray magnetic circular dichroism (XMCD), femtosecond demagnetization in nanoscale networks of magnetic domains is captured with sub-40-fs temporal and down to 19 nm spatial resolution [2]. This versatile ultrafast magneto-optical microscope will allow for comprehensive studies of ultrafast magnetism in space and time, compatible with applied external magnetic fields, currents, optical excitation and other in-situ capabilities. Furthermore, we believe that polarization-dependent ultrafast high harmonic imaging can be extended to other ultrafast phenomena, including structural dynamics and femtochemistry [3]. [1] Kfir, Zayko et al., Science Advances 3, no. 12, eaao4641(2017) [2] Zayko et al., Th1B.4. 10.1364/CLEOPR (2018) [3] Kraus et al., Nat. Rev. Chemistry 2, 82-94 (2018)