Analysis of thermal conductivity data in heavy fermion compounds

We present a revisiting analysis of thermal conductivity data in heavy fermion compounds. It is shown that the product WmagT, where Wmag is the magnetic part of the thermal resistivity taken as the difference between the inverse of the thermal conductivity of the Kondo compound and that of an equivalent non magnetic compound, is a good measurement of the strength of the Kondo interaction at sufficiently high temperatures with respect to the Kondo temperature and to the crystal-field splitting. In the considered temperature range, WmagT shows a log T dependence in a way similar to the magnetic part of the electrical resistivity. Such an analysis, which is analogous to the well known one for the electrical resistivity, has not been often used for the thermal conductivity. We present data for compounds with four anomalous Kondo rare earths Ce, Pr, Tm and Yb.