Influence of the Crystalline Field on the Kondo Effect of Alloys and Compounds with Cerium Impurities

The influence of the crystalline field on the Kondo effect of alloys with cerium impurities is studied in the framework of an effective Hamiltonian which describes the resonant-scattering character of the cerium impurities and which takes into account combined spin and orbit exchange scattering. The third-order perturbation-theory resistivity is computed exactly for any configuration of levels split by the crystalline field and is especially derived for the cases of two or three levels. The model is applied to the resistivity measurements of Ce${\mathrm{Al}}_2$ and Ce${\mathrm{Al}}_3$ compounds and to LaCe and YCe alloys. A general discussion of the magnetic and transport properties can explain the different roles of the cystalline field and of the Kondo effect for alloys with cerium impurities especially in the case of LaCe alloys.