Laser-driven resonant magnetic soft-x-ray scattering for probing ultrafast antiferromagnetic and structural dynamics

Time-resolved resonant magnetic scattering in the soft-x-ray range is a powerful tool for accessing the spatially resolved and element-specific spin dynamics in magnetic materials. So far, the application of this photon-demanding technique was limited to large-scale facilities. However, upgrades to diffraction-limited storage rings supporting only x-ray pulses beyond 100 ps, and the shift of x-ray free-electron lasers toward attosecond pulses aggravate the competition for beamtime in the picosecond time window, which is of utmost relevance for magnetism research. Here we present the development of a lab-based instrument providing sufficient photon flux up to 1.5 keV photon energy covering the soft-x-ray resonances of transition and rare-earth metal atoms. Our setup features the mandatory tunability in energy and reciprocal space in combination with sub-10 ps temporal resolution, exploiting the broadband emission of a laser-driven plasma x-ray source, which is monochromatized to about 1 eV bandwidth by a reflection zone plate. We benchmark our approach against accelerator-based soft-x-ray sources by simultaneously probing the laser-induced magnetic and structural dynamics from an antiferromagnetically coupled Fe/Cr superlattice. Our development charges, spins, and orbitals. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

Time-resolved resonant magnetic scattering in the soft-x-ray range is a powerful technique for studying spin dynamics in magnetic materials, but has been limited by the demand for photons and access to large-scale facilities. This study presents the development of a lab-based instrument capable of providing high-energy soft x-rays with sufficient photon flux and sub-10 ps temporal resolution for magnetism research.