Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 27: Magnetization / Demagnetization Dynamics I

MA 27.13: Vortrag

Mittwoch, 18. März 2015, 12:45–13:00, EB 301

Modelling of laser induced magnetization dynamics at very high magnetic fields — •Unai Atxitia — Zukunftskolleg and Department of Physics, Konstanz, Germany

Recently constructed high magnetic field labs connected to femtosecond laser pulse experiments will permit the measurement of the ultrafast magneto-optical properties of magnetic materials, allowing access to yet unexplored regimes of ultrafast non-equilibrium magnetisation dynamics. However, theoretical models of laser induced magnetisation dynamics assume applied magnetic fields as a second order effect, since it is usually very small in comparison to the strong exchange interactions present in ferromagnets. Thus, current models are not capable of adequately describing the magnetisation dynamics in the presence of high magnetic fields. Therefore further theoretical work is necessary in this line. Here, we present the extension to high fields of the widely used Landau-Lifshitz-Bloch equation of magnetisation dynamics. Within this model we compare the magnetisation dynamics induced by a laser pulse at different magnetic fields, from 0 to 50 Tesla. We show that very high magnetic fields can not only quantitatively but also qualitatively change the magnetisation dynamics after the laser pulse. It is expected that the predictions made within this model can be soon experimentally checked.