Crystal field multiplet calculations and the Magnetic circular dichroism of CrO2 in Resonant inelastic Xray scattering

X-ray spectroscopy is an effective tool to investigate the properties of a broad range of systems. With the advent of modern light sources and high resolution detection techniques, the X-ray Magnetic Circular Dichroism has since its early days evolved into a powerful method to study the magnetic momenta of many samples. Typical systems of interest are the 3d transition metals, where the magnetic circular dichroism is usually studied at the L2,3-edge utilising 2p X-ray absorption spectra. The L2,3-edge of 3d transitions metals lies in the soft X-ray energy range, which implies some experimental limitations in the direct 2p X-ray absorption spectra measurement. 1s2p Resonant Inelastic X-ray Scattering on the other hand has become an essential technique with respect to the investigation of the electronic structure. Since 2p X-ray absorption spectra and 1s2p Resonant Inelastic X-ray Scattering have the same final state electron configuration 1s2 2p5 3dN+1, one can take advantage of the hard X-rays used in 1s2p Resonant Inelastic X-ray Scattering to access soft X-ray information. The essential differences between the spectra obtained in 1s2p Resonant Inelastic X-ray Scattering and 2p X-ray absorption are illustrated in a series of crystal field multiplet calculations for the 3d transition metals covering each ground state between 3d0 and 3d9. We discuss in this context the influence of the intermediate state on the selections rules emphasising its importance when comparing 1s2p Resonant Inelastic X-ray Scattering and 2p X-ray absorption spectra. Furthermore, we combine 1s2p Resonant Inelastic X-ray Scattering and the X-ray Magnetic Circular Dichroism to measure the dichroic behaviour of the half-metal chromium dioxide (CrO2) using hard X-rays. We utilise this new combined approach on a CrO2 powder sample and complement the measurements with crystal field multiplet calculations to derive information about its electronic structure. We also performed the first angular dependent Magnetic Circular Dichroism and Natural Linear Dichroism measurements on CrO2 thin film samples …using the Resonant Inelastic X-ray Scattering technique, to take advantage of the highly ordered structure of the thin films. The measurements are then discussed in the final chapter in a qualitative way serving as a starting point for further studies