A Kondo lattice model for the phase diagram of CeSb at zero field

In this work we present a model to describe the different magnetic phases of CeSb as a function of temperature at zero magnetic field. A Kondo-Heisenberg-ANNNI model with Kondo and ferromagnetic interactions within the Ce planes together with first and second neighbor interplane spin interactions is proposed and solved using a mean-field approach inside the planes and an exact transfer matrix method along the easy direction of the magnetic planes. The total free energy of this effective one-dimensional model is computed and the lowest configurations are obtained by means of a Monte Carlo calculation. We find, within numerical resolution, most of the antierro-non-magnetic phases below the Neel temperature at zero field, thereby reproducing the data obtained by neutron diffraction. (C) 2000 Elsevier Science B.V. All rights reserved.