Phys.org  July 19, 2024 Rare-earth elements with strong magneto-crystalline anisotropy (MCA) are important ingredients for magnetic devices. Control of their localized 4f magnetic moments and anisotropy is one major challenge in ultrafast spin physics. An international team of researchers (Germany, Czech Republic, France, Sweden) used time-resolved x-ray absorption and resonant inelastic scattering experiments to show that for terbium that 4f-electronic excitations out of the ground-state multiplet occurred after optical pumping. These excitations were driven by inelastic 5d-4f-electron scattering, altering the 4f-orbital state and consequently the MCA with important implications for magnetization dynamics in 4f-metals and more general for the excitation […]