A simple approximation for Ising spin models

Michael Nauenberg

Weng Xiao-ming, Zhen‐Ya Li

A simple and powerful method (two-site effective field approximation) for mixed spin Ising model was presented. Our result about transition temperature of mixed Ising spin system is much better than that by making use of other approximate methods.

A. Bobák, S. Mockovčiak, J. Sivuľka

Abstract One‐ and two‐spin cluster approximations employing the differential operator technique are applied to study the second‐order phase boundaries for a quenched site‐diluted spin‐1 Ising model. The critical concentration below which the transition temperature reduces to zero is determined for the honeycomb, square, and simple cubic lattices. The results are compared to those of the site‐diluted spin‐1/2 Ising model.

Ken‐Yu Lin

P.W. Kasteleijn

Ilija M. Savić, L. J. Maurer

The authors extend to the S=1 Ising model a simple procedure which was proposed recently for the q-state Potts model. The approximate critical conditions are obtained for the ferromagnetic model on the square and simple cubic lattice.