Regensburg 2025 – scientific programme
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MA: Fachverband Magnetismus
MA 48: Ultrafast Magnetization Effects II
MA 48.1: Talk
Friday, March 21, 2025, 11:15–11:30, H20
Measurement of time resolved magneto-optic Kerr effect on ruthenium dioxide — •Holger Grisk1, Maik Gaerner2, Jakob Walowski1, Timo Kuschel2, and Markus Münzenberg1 — 1Institute of Physics, Greifswald University, Germany — 2Faculty of Physics, Bielefeld University, Germany
Altermagnetism is a novel fundamental phase of magnetism with exciting properties such as spin split bands.Ruthenium dioxide is one of the mostly investigated altermagnetic candidates. The antiparallel alignment of the Ru spins along with the anisotropic distribution of oxygen atoms leads to time reversal symmetry breaking and non-relativistic, anisotropic spin-splitting in the band structure. We used the time-resolved magneto-optic Kerr effect to measure the transient Kerr angle and reflectivity change after excitation with a femtosecond laser pulse to access the potential magnetic properties of ruthenium dioxide. The setup for the measurement exploits the pump-probe technique. A femtosecond laser pulse is split into a powerful pump and a low-power probe beam. The pump beam is used to photoexcite the electrons in the ruthenium dioxide. The probe beam is used to measure the shift in the Kerr rotation. Delaying the pump temporally and probing the evolution of the Kerr signal we can measure the ultrafast spin dynamics of ruthenium dioxide. The measurement shows Terahertz dynamics in the Kerr signal that is an order of magnitude faster than conventional ferromagnets. The studies were performed at room temperature and with small in plane magnetic field.
Keywords: ruthenium dioxide; Terahertz dynamics; magneto optic Kerr effect