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 have used both the full Hamiltonian, requiring heavy calculations of the local field, and a simplified version of it, obtained through a first order expansion of the local field. We find that, in both cases, the dipolar interaction induce a new and unexpected orientational order characterized by a depressed value of the orientational order parameter and by a corresponding enhanced value of .