THEORY OF THE THERMAL-CONDUCTIVITY OF RE AL-2 COMPOUNDS

On the basis of the variational method for transport coefficients we have calculated the thermal conductivity of RE Al-2-like systems as a function of temperature. The low-temperature limit obeys Matthiessen's rule 1/kappa = 1/kappa(ph) + 1/kappa(s) + 1/kappa(imp) where the three components are the contributions arising from e(-)-phonon, e(-)-localized spin and e(-)-impurity interactions, respectively. The temperature dependence of each term has been calculated, as well as the superposition of all three. The influence of the physical parameters (spin value, Debye temperature, cut-off wave vector, Fermi energy, etc.) is shown. The theory is in good agreement with reported data for GdAl2.