Kondo effect,spin dynamics and magnetism in anomalous rare earth and actinide compounds

The problem of magnetic ordering in Kondo lattices is discussed. Criteria of ferro- and antiferromagnetism in the mean-field approximation for thes-f exchange model are obtained. In the case of a constant bare DOS, the saturated Kondo ferromagnetic solution is energetically stable at small intersite interactionsJ. The role of spin-fluctuation corrections at lowT_K in the building up the low-energy scale and the ground state magnetization is considered. Renormalization of spin-fluctuation frequencies atT>T_K is calculated. A possible picture of the formation of magnetism is presented starting from the high-T limit.