Monte Carlo Studies of the Ising Antiferromagnet with a Ferromagnetic   Mean-field Term
  The unusual thermodynamic properties of the Ising antiferromagnet supplemented with a ferromagnetic, mean-field term are outlined. This simple model is inspired by more realistic models of spin-crossover materials. The phase diagram is estimated using Metropolis Monte Carlo methods, and differences with preliminary Wang-Landau Monte Carlo results for small systems are noted. 
Gregory Brown, Per Arne Rikvold, and Seiji Miyashita
cond-mat.stat-mech cond-mat.mtrl-sci