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MA: Fachverband Magnetismus
MA 21: Ultrafast Magnetization II
MA 21.5: Vortrag
Dienstag, 17. März 2020, 10:30–10:45, HSZ 101
Ultrafast lattice dynamics of 3d ferromagnets — •Daniela Zahn1, Florian Jakobs2, Tim Butcher3, Thomas Vasileiadis1, Yoav William Windsor1, Dieter Engel4, Helene Seiler1, Yingpeng Qi1, Unai Atxitia2, Jan Vorberger3, and Ralph Ernstorfer1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany — 2Freie Universität Berlin, Berlin, Germany — 3Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 4Max-Born-Institut, Berlin, Germany
The behavior of ferromagnets after laser excitation is governed by the interplay of electrons, lattice and spins. In the case of 3d-ferromagnets, strong coupling between electrons and spins leads to ultrafast demagnetization on the femtosecond time scale. The lattice plays an important role in the magnetization dynamics, since it drains energy from the electrons on similar timescales and absorbs angular momentum from the spin system. Here, we study the lattice response of the 3d ferromagnets nickel, iron and cobalt directly using femtosecond electron diffraction (FED). We find excellent agreement of the experimental results with DFT calculations in combination with a modified two-temperature model (TTM) that assumes strong coupling between electrons and spins. In addition, we compare the experiment to atomistic spin simulations. Our results suggest that energy transfer between electrons and spins on ultrafast timescales has a strong effect on the lattice dynamics.