What about the crystal field effects in the CeFe4Sb12 resistivity behavior?

The thermal variation of the resistivity of CeFe4Sb12 shows a drop below 150 K when the temperature decreases. Up to now, this behaviour has been explained by the onset of the coherent scattering of the charge carriers by the cerium sublattice. Another explanation is the crystal electric field (CEF) effect. We have performed resistivity experiments on the solid solution Ce1-xLaxFe4Sb12 in order to confirm one of these two hypotheses. The cerium resistivity (ρ(Ce1-xLaxFe4Sb12) - ρ(LaFe4Sb12)) shows a maximum around 150 K for all cerium concentrations. So that the CEF effect hypothesis seems the best one. Also, inelastic neutron scattering experiments have been performed on CeFe4Sb12 and LaFe4Sb12. (author)