SKM 2023 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 23: Poster Magnetism I
MA 23.70: Poster
Dienstag, 28. März 2023, 17:00–19:00, P1
Ultrafast magnetization precession in metallic heterostructures driven by different excitation mechanisms — •Jasmin Jarecki1, Maximilian Mattern1, Jan-Etienne Pudell1,2,3, Michel Hehn4, Fried Weber1, Alexander von Reppert1, and Matias Bargheer1,2 — 1Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany — 2Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany — 3European X-Ray Free-Electron Laser Facility, Schenefeld, Germany — 4Institut Jean Lamour (UMR CNRS 7198), Universite Lorraine, Nancy, France
We study the magnetization precession induced by different excitation mechanisms, i.e. ultrafast demagnetization, temperature dependent anisotropy change and magneto-elastic coupling, in 20 nm Ni films within PtCuNi-heterostructures. The samples are excited by an ultrashort laser pulse from the Pt side and designed such that light does not excite Ni directly. The indirect excitation of the Ni is tailored in different ways: strain waves, heat waves and/or hot electrons. We combine time-resolved x-ray diffraction (UXRD) and magneto-optical Kerr effect measurements (MOKE) under variation of the external field angle to access the strain dynamics and therefore also the energy transfer within the sample and the out-of-plane component of the Ni magnetization. We observe a distinct angle-dependence of the precession amplitude depending on the predominant excitation mechanism. While temperature related effects cause high amplitudes for nearly out-of-plane external fields, recurring strain pulses amplify the amplitudes resonantly around 50∘.