INTERNATIONAL JOURNAL OF MODERN PHYSICS B, vol.25, pp.2895-2903, 2011 (SCI-Expanded)
In this work, we present a simple approximate transfer matrix method for 2D and 3D Ising ferromagnet to calculate spontaneous magnetization of the system. The critical coupling strength K-c of 2D and 3D Ising models in reduced transfer matrix approximation is obtained quite accurately by simple improvements over the mean field theory. The important physical effect we include is the some of the fluctuations effects of the systems directly with help of this method. We predict from the spontaneous magnetization curve that the critical coupling strength K-c = J/k(B)T = 0.401 and 0.245 for two-dimensional (2D) and three-dimensional (3D) systems, respectively.