Blume–Capel model on the antiferromagnetic fcc lattice

In the presence of a uniform external magnetic field, the spin-1 fcc antiferromagnetic Ising model in the four sub-lattice with the nearest-neighbor bilinear and crystal field interactions is investigated by using mean-field theory. The lattice is considered in blocks and each block contains 32 spins. While the central four spins forming a basic tetrahedron structure are allowed to fluctuate, the surrounding 28 spins take the mean-field values. The ground state phase diagram of the system is examined since it provides valuable information to make a prediction of the different phase diagram topologies. The phase diagrams are obtained on the reduced external field versus temperature, ( H / | J | − k T / | J | ) , plane for selected crystal field interaction values from the ground state phase diagram and it is found that the system exhibits reentrant behavior and some special points such as tricritical, bicritical and triple points.