Kondo effect, crystalline electric fields and itinerant magnetism in antimony-based filled skutterudites

Abstract In CeFe 4 Sb 12 , itinerant paramagnetism from iron and localized paramagnetism of cerium coexist. For the cerium contribution to the electrical resistivity ρ Ce ( T ), magnetic susceptibility χ Ce ( T ) and heat capacity Δ C P ( T ), we find a maximum at around 130 K. Below 2 K, non-Fermi liquid behaviour is evidenced from our heat capacity measurements on CeFe 4 Sb 12 . The invariance of the maximum to ρ Ce ( T ) upon substituting La for Ce indicates that the crystalline electric fields splitting ( Δ CEF ) has to be considered in addition to the Kondo effect with high Kondo temperature T K and Δ CEF / T K ≈5.