MAGNETIC CORRELATIONS IN THE KONDO-LATTICE - THE DONIACH DIAGRAM REVISITED

A Kondo lattice model, including nearest-neighbor magnetic correlation s, is studied within a generalized mean-field approximation. We comput e the correlation functions between localized and conduction electrons on the same site and between localized electrons on different sites. The Kondo temperature T-K and a neighbor correlation temperature are d etermined and the results compared with the Doniach diagram. We obtain a saturation and even a decrease of T-K as a function of the Kondo co upling; this can account for experimental results in some cerium compo unds. (C) 1998 Elsevier Science B.V. All rights reserved.