A discussion of mean –field theory in Ising spin models

Abstract

IN this work an isospin system with spin values is studied through introducing improvement on a mean-field method for Ising spin system. The method is based on an extended Oguchi approximation (OA) . Within this scheme, three atoms are considered where the two nearest –neighbour spin correlation are taken into account when the Hamiltonian is presented .The result obtatined for the Curi temp. are more accurate compared with mean-field approximation (MFA) and Oguchi models Atable is stateed for comparison purposes , bet the present results and that of Curi temp. for approximation refeed earliear respectively.