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

In CeFe4Sb12, itinerant paramagnetism from iron and localized paramagnetism of cerium coexist. For the cerium contribution to the electrical resistivity rho(Ce)(T), magnetic susceptibility chi(Ce)(T) and heat capacity Delta 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 CeFe4Sb12. The invariance of the maximum to rho(Ce)(T) upon substituting La for Ce indicates that the crystalline electric fields splitting (Delta(CEF)) has to be considered in addition to the Kondo effect with high Kondo temperature T-K and Delta(CEF)/T-K approximate to 5. (C) 2003 Published by Elsevier B.V.