CRYSTAL-FIELD EFFECTS ON THE THERMAL-CONDUCTIVITY OF LOCALIZED SPIN METALLIC COMPOUNDS

The influence of the crystal-electric-field (CEF) splitting on the the rmal conductivity is calculated on the basis of a two-level system mod el applicable to intermetallic magnetic compounds. The localized spin scattering contribution kappa(s), in a manner similar to the total ele ctronic thermal conductivity kappa(e), shows a larger increase at low and intermediate temperatures as compared to the case iii which-no cry stal-electric-field splitting is taken into account. The influence of some theoretical parameters is also discussed. It is shown that the CE F effect enhances the effect of the magnetic scattering potential, and impurity contributions screen such an enhancement at temperatures bel ow the Debye temperature. Other scattering contributions, e.g., electr on-phonon and electron impurities, are also taken into account in our calculation. The theory is in quantitative agreement with data on RA1( 2) systems taken as test cases, and leads to values of the level split ting in the 50 K range.