Monte Carlo Metropolis simulation of interacting anisotropic polarizable spins on a lattice

We present a Monte Carlo Metropolis computer simulation study of the equilibrium configurations of a spin lattice model of anisotropically polarizable particles. In the presence of an external field the spins polarize and couple via dipolar interactions. To simulate the system we used both the complete Hamiltonian, requiring heavy calculations of the local field, and a simplified version, obtained by a first order expansion of the local field. We find that in both cases, the dipolar interaction induces a new and unexpected orientational order characterized by a depressed value of the orientational order parameter [P-2] and by a corresponding enhanced value of [P-4]. (C) 2001 Elsevier Science B.V. All rights reserved.