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MA: Fachverband Magnetismus

MA 42: Posters Magnetism I

MA 42.28: Poster

Mittwoch, 18. März 2020, 15:00–18:00, P3

Time resolved magnetostriction in itinerant ferromagnet SrRuO₃ — Maximilian Mattern¹, •Jan-Etienne Pudell¹, Alexander von Reppert¹, Marc Herzog¹, and Matias Bargheer^1,2 — ¹Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany — ²Helmholtz-Zentrum Berlin, Berlin, Germany

We present ultrafast x-ray diffraction (UXRD) measurements of the ferromagnet SrRuO₃ using 200 femtosecond x-ray pulses derived from a laser based plasma x-ray source. Optical excitation of a 20 nm SrRuO₃ layer by femtosecond laser pulses instantaneously heats up the electron gas. In the paramagnetic phase the deposited energy couples to the phonons and leads to a lattice expansion. In the ferromagnetic phase a part of the deposited energy is transferred to the spin degrees of freedom. This results in a reduced lattice expansion in the ferromagnetic phase due to a pronounced magnetostriction. In the ferromagnetic phase of SrRuO₃ the energy transferred from the electrons to the spin system leads to a lattice contraction, whereas heating the phonon system leads to expansion. We model the generated lattice dynamics after laser excitation and analyze the saturation of the spin excitation upon systematic variation of the starting temperature and excitation fluence.