An approximation in the cluster variation method (CVM) is used to investigate the modulated phases as well as the critical temperatures of the 2D and the 3D ANNNI models. It is first found that it shows the existence and the non-existence of the Lifshitz points in the 3D and the 2D model,...

The asymptotic behavior of the spin pair correlation function along an axis is investigated for the Ising model on a brickwork lattice with second neighbor interactions. It is suggested that some of long-range phase predicted by the mean-field appriximation arereflected in the asymptotic...