The spin- sandwiched trilayer Bethe lattices

The Ising model for the spin- sandwiched trilayer Bethe lattices is investigated in terms of the recursion relations with either ferromagnetic (FM) or antiferromagnetic (AFM) type of bilinear interactions between the nearest-neighbor (NN) spins. In addition to the ground-state (GS) phase diagrams, the thermal variations of the order-parameters, spin–spin correlation functions and free energies are studied; therefore, different topological temperature-dependent phase diagrams are obtained. It was found that the system exhibits second- and first-order phase transitions. The bicritical, critical end and multicritical points, and the stable and unstable tricritical points are observed in addition to the reentrant behavior for the coordination numbers q=3, 4 and 6.