Berlin 2024 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 38: Ultrafast Magnetization Effects III

MA 38.2: Vortrag

Donnerstag, 21. März 2024, 11:30–11:45, EB 202

Picosecond X-ray magnetic circular dichroism with a laser-driven plasma source — •Konstanze Korell, Martin Borchert, Leonid Lunin, Daniel Schick, and Stefan Eisebitt — Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin

X-ray magnetic circular dichroism (XMCD) combines large magnetic contrast with element-selectivity, and access to buried layers. In the soft-X-ray range at the 3d transition metal L and rare earth M edge (500-1500 eV), so-called sum-rules even allow to disentangle the spin and orbital angular momentum. However, XMCD spectroscopy requires soft X-rays with circular polarization, limiting this powerful technique to accelerator-based large-scale facilities such as synchrotrons and free-electron lasers. Recently, we have demonstrated the first laboratory-based XMCD experiment at the Fe L-edges outside of large-scale facilities using laser-driven plasma X-ray source (PXS) in combination with a ferrimagnetic polarizer to generate partially circular polarization. In this contribution, I will present the design and specifications of our new beamline dedicated for time-resolved XMCD spectroscopy. The setup features an extremely broad spectral range from 50-1500 eV with a 40 µm (FWHM) X-ray focus and sub-10 ps temporal resolution. Further, I will present and discuss first results towards time-resolved XMCD spectroscopy on a FeGd multilayer sample after photoexcitation.

Keywords: XMCD; time-resolved; FeGd; plasma X-ray source; tabletop