PHASE-TRANSITIONS IN A SPIN-1 MODEL WITH PLAQUETTE INTERACTION ON THESQUARE LATTICE

Citation
C. Buzano et al., PHASE-TRANSITIONS IN A SPIN-1 MODEL WITH PLAQUETTE INTERACTION ON THESQUARE LATTICE, Physical review. B, Condensed matter, 53(22), 1996, pp. 15063-15070
Citations number
36
Categorie Soggetti
Physics, Condensed Matter
ISSN journal
01631829
Volume
53
Issue
22
Year of publication
1996
Pages
15063 - 15070
Database
ISI
SICI code
0163-1829(1996)53:22<15063:PIASMW>2.0.ZU;2-1
Abstract
An extension of the Blume-Emery-Griffiths model with a plaquette four- spin interaction term, on the square lattice, is investigated by means of the cluster variation method in the square approximation. The grou nd state of the model, for negative plaquette interaction, exhibits se veral new phases, including frustrated ones. At finite temperature we obtain a quite rich phase diagram with two new phases, a ferrimagnetic and a weakly ferromagnetic one, and several multicritical points.