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MA: Fachverband Magnetismus
MA 38: Ultrafast Magnetization Effects II
MA 38.2: Vortrag
Mittwoch, 11. März 2026, 15:15–15:30, POT/0361
Interfacial magnon generation drives ultrafast spin dynamics in Gd — •Corvin Krohn1, Ekaterina Bobrova1, Tim Amrhein1, Dominic Lawrenz1, Niko Pontius2, Christian Schüssler-Langeheine2, Martin Weinelt1, and Nele Thielemann-Kühn1,2 — 1Freie Universität Berlin, Berlin, Germany — 2Helmholtz-Zentrum Berlin, Berlin, Germany
Previous time-resolved photoemission [1] and x-ray magnetic circular dichroism (XMCD) [2] experiments investigating 4f magnetization dynamics in Gadolinium (Gd) showed conflicting results, with demagnetization timescales of 14 ps [1] and 0.7 ps [2], respectively.
Within an XMCD study at the FemtoSlicing facility, we could now show that intrinsic dynamics in Gd is slow. For a thin Gd film, however, where the pump laser directly excites the non-magnetic substrate as well, generation of magnons at the metal-substrate interface drives the ultrafast demagnetization.
In the next step we aim to identify magnons as ms state excitations within the Gd 4f electronic ground level, using time-resolved x-ray absorption spectroscopy.
Revealing signatures of magnetic dynamics in the electronic structure will provide insights into the correlated electronic and magnetic structure of 4f metals.
[1] B. Frietsch et al., Nat. Commun. 6, 8262 (2015).
[2] K. Bobowski et al., J. Phys.: Condens. Matter 29, 234003 (2017).
Keywords: ultrafast spin dynamics; time-resolved x-ray absorption spectroscopy; magnons; magnon generation; gadolinium