Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 85: Ultrafast Electron Dynamics at Surfaces and Interfaces II: New Methods and Developments

O 85.1: Vortrag

Donnerstag, 4. April 2019, 15:00–15:15, H16

The role of the spin-orbit interaction and the exchange interaction in the ultrafast demagnetization of antiferromagnetic RE intermetallics — •S.E. Lee¹, Y.W. Windsor¹, D. Zahn¹, K. Kliemt², C. Krellner², K. Kummer³, C. Schüßler-Langeheine⁴, N. Pontius⁴, D.V. Vyalikh^5,6, U. Staub⁷, and L. Rettig¹ — ¹FHI, Faradayweg 4-6, 14195 Berlin, Germany — ²Physik. Institut, Uni. Frankfurt, Max-von-Laue Straße 1, 60438 Frankfurt am Main, Germany — ³ESRF, 71 Avenue des Martyrs, CS40220, F-38043 Grenoble Cedex 9, France — ⁴BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany — ⁵DIPC, 20080 San Sebastian, Spain — ⁶IKERBASQUE, 48011 Bilbao, Spain — ⁷SLS, 5232 Villigen PSI, Switzerland

We have investigated the ultrafast dynamics of the antiferromagnetic rare-earth intermetallics, GdTM₂Si₂ (TM = Rh, Ir) employing time-resolved resonant magnetic soft X-ray scattering, which directly probes the transient 4f magnetic order. Following excitation by 40 fs pulses at 1.5 eV, GdTM₂Si₂ shows ultrafast demagnetization, which can be described by two exponential functions, one on a subpicosecond timescale and the other one on a tens of picoseconds timescale. While both compounds behave qualitatively very similar, GdIr₂Si₂ demagnetizes for a given fluence slightly more but with a slower time constant than GdRh₂Si₂. By comparing these two materials we will discuss the importance of the spin-orbit interaction and the exchange interaction for the ultrafast demagnetization for these antiferromagnetic materials.