Multicritical points in the mixed spin-1 and spin- Ising system on a square lattice with different single-ion anisotropies

Using an effective-field theory we study a multicritical behaviour of the mixed spin-1 and spin- Ising model with different anisotropies on a square lattice. We find a variety of topologies of the finite-temperature phase diagrams, with several multicritical points. The highest-order multicritical entity is the fourth-order point, which contradicts earlier results obtained within the same theoretical framework