Phase transition in the dipole-interaction Ising model at negative absolute temperatures

A modification of the Monte-Carlo method is developed for the statistical modeling of lattice systems with dipole-dipole interaction. A representation of the dipole Hamiltonian in reciprocal space is used in the computations. The phase transition in the antiferromagnetic Ising model with pure dipole interaction is investigated at negative absolute temperatures on the basis of the method proposed. Thermodynamic properties of the model are calculated and the critical point is determined. The results of the machine experiment differ significantly from the predictions obtained by the molecular field method.