Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 64: Poster 1

MA 64.57: Poster

Freitag, 24. März 2017, 09:30–13:00, P2-EG

Photon energy dependent fs-demagnetization dynamics of thin Ni films — •Jonas Hoefer, Sebastian Weber, Ute Bierbrauer, David Schummer, Moritz Barkowski, Benjamin Stadtmüller, Bärbel Rethfeld, and Martin Aeschlimann — Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger-Strasse 46, 67663 Kaiserslautern, Germany

After the first observation of the ultrafast demagnetization process of ferromagnetic thin films on the femtosecond timescale, a huge experimental and theoretical effort was devoted to reveal the microscopic mechanism governing the ultrafast optically induced loss of magnetic order in ferromagnetic materials.

In this context, almost all experimental studies so far employed fs light pulses of 1.55eV to trigger the fs-demagnetization dynamics. Hence, the role of the photon energy of the exciting light pulse has not been investigates so far. Therefore, we have implemented an all optical time resolved MOKE setup with variable pump photon energy in the range of 1.55 to 3.10eV. As prototypical system, we first investigated the ultrafast demagnetization dynamics of thin Ni films on insulating and conducting substrates for various excitation photon energies. The characteristic parameters of the demagnetization process, i.e., the demagnetization time and the quenching of magnetization, will be compared to simulations describing the non-equilibrium dynamics of the spin-carrying excited electrons.