Berlin 2018 – scientific programme

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MA: Fachverband Magnetismus

MA 14: INNOMAG e.V. Dissertationspreis 2018 / Ph.D. Thesis Prize

MA 14.4: Invited Talk

Monday, March 12, 2018, 16:15–16:40, H 0112

Optically induced ferro- and antiferromagnetic dynamics in the rare-earth metal dysprosium — •Nele Thielemann-Kühn — Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin, Germany — Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany

By comparing ferro- and antiferromagnetic dynamics in one and the same material -metallic dysprosium- we show both to behave fundamentally different. Antiferromagnetic order is considerably faster and much more efficiently manipulated by optical excitation than its ferromagnetic counterpart. Within a depth-resolved study of optically induced antiferromagnetic dynamics we find the magnetic order to be suppressed by a long-ranging process. We assign this fast and extremely efficient mechanism to an interatomic transfer of angular momentum within the spin-system via fast diffusion of excited valence electrons. On longer picosecond-timescales the antiferromagnetic order is further reduced only in regions where the laser directly excited the sample. In addition we observe two clearly distinguishable regions with different magnetic properties within the sample hinting to a long-living non-equilibrium state of the 4f-magnetic system. The complex depth dependent quenching behavior of the antiferromagnetic order is indicative for the interplay of different delocalized as well as local spin-scattering channels.