Comparison between experimental XANES spectra and electronic structure calculations in the filled skutterudites CeyFe4-xNixSb12

For some years filled skutterudites have been the subject of great interest owing to their promising thermoelectric properties. Their simple cubic structures is associated with complex fundamental physical properties, thanks to itinerant (Fe,Ni) and localized (Ce) magnetism. Their electronic structure proved to be complex and has been studied both by experimental and theoretical means. We have performed X-ray absorption measurements at the L and M edges of Ce, Fe and Ni on the cerium filled nickel substituted skutterudites Ce_yFe_4-xNi_xSb₁₂. Those experimental results are compared to first principles calculations (WIEN97) and multiple scattering XANES simulations (FDMNES). The comparison shows good agreement between experimental and calculated spectra. Calculations confirm the predominance of itinerant magnetism versus localized magnetism for iron: both density of states (DOS) and electronic density for spin up and spin down electrons are almost identical. Simulations and DOS for several compositions will be presented at various edges for Fe, Ni and Ce.