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MA: Fachverband Magnetismus
MA 30: Ultrafast Magnetization III
MA 30.5: Vortrag
Mittwoch, 18. März 2020, 10:30–10:45, HSZ 101
Probing strain as a proxy for magnetic ordering in a rare earth metal — •Alexander von Reppert1, Maximilian Mattern1, Jan-Etienne Pudell1, Steffen Zeuschner1,2, Karine Dumesnil3, and Matias Bargheer1,2 — 1Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany — 2Helmholtz-Zentrum Berlin, Berlin, Germany — 3Institut Jean Lamour (UMR CNRS 7198), Université Lorraine, Nancy, France
Optical excitation of spin-ordered rare earths triggers a complex response of the crystal lattice, since expansive stresses from electron and phonon excitations compete with a sizable contractive stress induced by spin disorder. Using ultrafast X-ray diffraction experiments we study the layer specific strain response of a Dysprosium film adjacent to a non-magnetic detection layer upon fs laser-excitation. Both the picosecond strain pulse and the thermal transport show signatures of a sizable energy transfer to magnetic excitations in the rare earth. The modeled rise times of the magnetic stress are in close agreement with the recently reported demagnetization timescales, which shows that the strain response can serve as a proxy for the time-dependent magnetic ordering in both antiferromagnetic and ferromagnetic rare earths. We experimentally corroborate this finding using a two-pulse excitation scheme, wherein the first laser pulse changes the magnetic state, while the second pump pulse triggers a lattice response that strongly depends on the degree of disorder of the spin system.