SKM 2021 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 11: Posters Magnetism III

MA 11.6: Poster

Mittwoch, 29. September 2021, 13:30–16:30, P

Combined tr-MOKE, BLS and THZ-radiation setup for the investigation of magnetization dynamics on different time scales — •Akira Lentfert¹, Benjamin Stadtmüller¹, Martin Aeschlimann¹, Georg von Freymann^1,2, and Philipp Pirro¹ — ¹Fachbereich Physik and Landesforschungszentrum OPTIMAS, TU Kaiserslautern — ²Fraunhofer Institute for Industrial Mathematics ITWM

Two separate models commonly describe spin and magnetization dynamics on different time scales. Systems in the sub-picosecond regime in ultrafast demagnetization processes are dominated by single-particle excitations. Here, a femtosecond laser pulse induces a loss of the magnetic order, which can be observed with time-resolved pump-probe spectroscopy based on the magneto-optical Kerr effect (tr-MOKE). In the nanosecond time scale, dynamics are described by collective excitations in terms of spin waves. However, due to the nature of the measurement technique mentioned above, it is impossible to detect incoherent collective dynamics. Therefore, the role of spin-waves up to the THz regime on ultrashort time scales could not be studied sufficiently. In this work, a combined setup of tr-MOKE with Brillouin-Light-Scattering spectroscopy (BLS) is presented, which allows the simultaneous investigation of magnetization dynamics on different time scales, from 1 ns down to 10 fs. Furthermore, using electromagnetic THz radiation to excite spin waves in this frequency regime resonantly gives further insight into the magneto-optical interactions. This research has been supported by DFG (TRR 173: Spin+X).