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MA: Fachverband Magnetismus
MA 31: Poster II
MA 31.15: Poster
Mittwoch, 19. März 2025, 17:00–19:30, P1
Element-resolved study of antiferromagnetic/ferromagnetic magnetization dynamics in epitaxial CoO/Fe bilayer — •Chowdhury Shadman Awsaf1, Sangeeta Thakur1, Markus Weißenhofer2, Jendrik Gördes1, Marcel Walter1, Niko Pontius3, Christian Schüßler-Langeheine3, Peter Oppeneer2, and Wolfgang Kuch1 — 1Institut für Experimentalphysik, Freie Universität Berlin — 2Department of Physics and Astronomy, Uppsala University — 3Helmholtz-Zentrum Berlin für Materialien und Energie
We examine the transient AFM spin structure in an epitaxial Fe/CoO bilayer on an Ag(001) single-crystal substrate after excitation by 60 fs laser pulses of 800 and 400 nm wavelength, below and above the CoO band gap, respectively, by evaluating the time-resolved x-ray magnetic linear dichroism in reflectivity at the Co L2 edge. The findings are compared to time-resolved x-ray magnetic circular dichroism measurements at the Fe L3 edge. Both layers exhibit a fast drop in magnetic order within 300 fs. Simulating an atomistic two-temperature model, coupled with the stochastic Landau Lifshitz-Gilbert equation for the spin degrees of freedom, indicates a direct energy transfer from hot Fe electrons to CoO spins in the case of 800 nm excitation. For demagnetization at 400 nm pump, above-band-gap excitation in CoO has to be assumed in the simulation to reproduce the experimental result [1]. [1] C. S. Awsaf et al., arXiv:2408.14360.
Keywords: AFM spin structure; time-resolved x-ray magnetic linear dichroism; time-resolved x-ray magnetic circular dichroism; atomistic two-temperature model; band-gap excitation