A frustrated Kondo lattice model for the magnetic phases of CeSb

We present a model to describe the phase diagram of CeSb near the critical temperature. This compound is well known because it presents many different ordered phases as a function of temperature and magnetic field. We propose a frustrated Kondo lattice model with first- and second-neighbor interplan e spin interactions, and solve this model using a generalised mean field ap proach within the planes and an exact transfer matrix method along the easy direction of the magnetic planes. Different magnetic configurations are ob tained by minimising the total free energy and the modulated phases with "p aramagnetic planes" can be understood in terms of a frustration mechanism o f a Kondo-type effect. (C) 1999 Published by Elsevier Science B.V. All righ ts reserved.