Phase diagrams of spin-3/2 Blume–Capel model on rectangular lattice under longitudinal magnetic field

The spin-3/2 Blume–Capel model on a rectangular lattice with the ferromagnetic bilinear short-range interaction KF=K(1+x)KF=K(1+x) in one direction and the anti-ferromagnetic one KAF=K(−1+x)KAF=K(−1+x) in the perpendicular direction under a longitudinal magnetic field and in the presence of a single-ion anisotropy is investigated within the mean field approximation. The quantity x characterizes coupling between the interactions in the perpendicular directions and its absolute value does not exceed unity. Basing on the study of temperature dependencies of sublattice magnetizations the phase diagrams in the (x, temperature) plane are constructed for different values of the longitudinal magnetic field and the single-ion anisotropy. The global phase diagram of the model demonstrates an unusual abundance.