ANTIFERROELECTRIC TRANSITION IN beta -ALUMINA, A REALIZATION OF THE D equals 2, s equals 3 POTTS MODEL?

A model based on electric dipole-dipole interactions is proposed to explain the recently observed ordering transition in stoichiometric silver beta -alumina. The low temperature phase is a three-fold degenerate antiferroelectric array of dipoles associated with Ag** plus and O//5** minus ** minus ions. When T yields T//c with (T minus T//c)/T//c greater than 10** minus **2, the correlation length zeta increases in the D equals 2 layers with a critical behavior zeta similar (T minus T//c)** minus **v which is supposed to belong to the D equals 2, s equals 3 Potts model universality class: we find v//e//x//p equals 0. 85 plus or minus 0. 1 as v//t//h similar 0. 83.