Comparison betweenXANES experimental spectra and electronic structure calculations in the filledskutterudites (Ce_yFe_4-xNi_xSb₁₂)

F. Lemoigno¹,M.-L. Doublet¹, L. Chapon², J. C. Tedenac², D.Ravot²

¹Laboratoirede Structure et Dynamique des Systèmes Moléculaires et Solides,UMR 5636, Université de Montpellier 2, 34095 Montpellier cedex 5, France

²Laboratoire de Physico-chimie dela Matière Condensée, UMR 5617, Université de Montpellier2, 34095 Montpellier cedex 5, France

For some years the filled skutterudites have been the subject ofgreat interest due to their promising thermoelectric properties. Their simplecubic structure is associated to complex fundamental physical properties, owingto the presence of itinerant (Fe, Ni) and localized (Ce) magnetism. Theirelectronic structure proved to be complex and has been studied both byexperimental and theoretical means.

Wehave performed X-Ray absorption measurements at the L and M edges of Ce, Fe, Niand Sb on the cerium filled nickel substituted skutterudites Ce_yFe_4-xNi_xSb₁₂.Those experimental results are compared to first principles periodic electronicstructure calculations (Wien97) and multiple scattering XANES simulations(FDMES). The comparison shows a good agreement between experimental andcalculated spectra. The calculations confirm the predominance of itinerant magnetism versus localizedmagnetism for iron: both density of states (DOS) and electronic densityassociated with spin-up and spin-down electrons are almost identical.Simulations and DOS for different compositions will be presented at variousedges for iron and cerium.