Pressure dependence of the electrical resistivity of the filled skutterudites LnFe4Sb12 (Ln = Ce, Yb)

We report the pressure dependence of the electrical resistivity of two filled skutterudite compounds YbFe4Sb12 and CeFe4Sb12 from 1.2 K up to room temperature and under applied pressures up to 17 kbar. Both YbFe4Sb12 and CeFe4Sb12 show a rapid decrease of rho at similar to 50 K and similar to 100 K, respectively, which is caused by the onset of coherent scattering of electrons from the rare-earth sublattice. The resistivity curves can be collapsed onto the ambient pressure curve using a single scaling temperature T-0, indicating that a single characteristic energy dominates the transport properties. For CeFe4Sb12, T-0 is found to increase with pressure, while the opposite behaviour is observed for YbFe4Sb12. The pressure dependence of rho as well as the change of T-0 are similar to the findings for a number of other intermediate-valence and heavy-fermion systems.