Monte Carlo simulation of type-1 fcc Ising antiferromagnets

Using Monte Carlo methods we investigate the phase transition of an Ising system on the fcc lattice, with antiferromagnetic nearest-neighbor interaction $J$ and ferromagnetic next-nearest-neighbor interaction $\alpha J$ for α values up to 2. The scaling of the microcanonical entropy $s_L$ with system size $L$ agrees with the assumption of a first-order transition. Since the asymptotic behavior has not yet been reached, even for the largest systems with $L=40,$ our calculations cannot determine the order of the transition unambiguously.