Antiferromagnetic Spherical Ising Model and Some Properties of the Associated Lattice Gas

Abstract

The spherical model of Berlin and Kac is applied to an antiferromagnetic interaction. The critical‐field curve, magnetization‐field curves, specific heats, and long‐range order are calculated. The problem is translated into lattice‐gas language, to afford a possible model for the solid—gas transition. Very unphysical behavior is found, and a probable reason is discussed. This is ascribed to a ``borrowing'' of spin from one sublattice by the other.