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MA: Fachverband Magnetismus

MA 18: Posters Magnetism V

MA 18.39: Poster

Friday, October 1, 2021, 10:00–13:00, P

Optical control of 4f orbital state in rare-earth metals — N. Thielemann-Kühn¹, •T. Amrhein¹, W. Bronsch¹, S. Jana², N. Pontius², R. Engel³, P. Miedema³, D. Legut⁴, K. Carva⁵, U. Atxitia¹, B. Van Kuiken⁶, M. Teichmann⁶, R. Carley⁶, L. Mercadier⁶, A. Yaroslavtsev^6,7, G. Mercurio⁶, L. Le Guyader⁶, N. Agarwal⁶, R. Gort⁶, A. Scherz⁶, M. Beye³, P. Oppeneer⁷, M. Weinelt¹, and C. Schüßler-Langeheine² — ¹Freie Universität Berlin — ²HZB — ³DESY — ⁴IT4Innovations — ⁵Charles University — ⁶European XFEL — ⁷Uppsala University

High density magnetic storage devices base on materials with large magneto crystalline anisotropy (MCA) that needs to be overcome by laser heating above the Curie temperature to enable bit writing [1]. In a time-resolved X-ray absorption experiment at the European XFEL we found that the MCA itself can be manipulated on fs time scales by an optical stimulus [2]. In 4f rare-earth metals the magnetic moment and high MCA stems from the 4f system that is not directly accessible with optical wavelengths. We show, however, that the direct excitation of 5d electrons drives 4f-5d inelastic electron scattering and 4f-5d electron transfer, initiating orbital excitations in the 4f shell that change the MCA tremendously. Besides the technological relevance of such handle on MCA, 4f electronic excitations directly alter exchange and electron-phonon coupling and thus contribute to a more fundamental understanding of non-equilibrium dynamics.

[1] W. Challener et al. Nature Photon 3, 220-224 (2009).

[2] arXiv:2106.09999