An effective field study of the staggered quadrupolar phase in the BEG model

Abstract

The so-called new effective field theory, based on a finite cluster theory that correctly incorporates the single-site kinematic relations, is applied to the Blume Emery Griffiths (BEG) model with positive biquadratic interactions in order to test its ability to deal with magnetic systems having competing interactions. In particular, the region of the phase diagram containing a staggered quadrupolar phase is explored and comparison with the results of Monte Carlo simulation made. The results are also compared to those obtained by a cluster variation method in pair approximation.