Mean-field transfer-matrix study of the magnetic phase diagram of CsNiF$_{\bf 3}$

Abstract

A method for treating ferromagnetic chains coupled with antiferromagnetic interactions on an hexagonal lattice is presented in this paper. The solution of the $1D$ part of the problem is obtained by classical transfer-matrix while the coupling between the chains is processed by mean-field theory. This method is applied with success to the phase diagram and angular dependence of the critical field of CsNiF$_3$. Results concerning the general influence of single-ion anisotropy on the magnetic ordering of such systems are also presented.