Ground state phase diagrams for the mixed Ising 2 and 5/2 spin model

•Ground state phase diagrams are examined for the mixed spins 2 and 5/2 Ising system on a bipartite square lattice.•The ground state energies of the system are numerically calculated and the phase diagrams in an exact form enumerating all possible states of the system.•The proposed Hamiltonian includes nearest-neighbor interactions, second neighbors and crystal fields.•Multiphase points of each region of ground state are analyzed.

We investigate the behavior of ground state phase diagrams of a mixed Ising spins model on a bipartite square lattice of spins SiA=2 and σjB=5/2. The proposed Hamiltonian includes coupling to first and second neighbors, and crystal field interactions between sublattices. In the phase diagrams, according to the combination of the parameters in the Hamiltonian, multiphase points, disordered regions, and various structures are presented. Phase diagrams of the ground state are useful to check the reliability of the numerical results for the phase diagrams at finite temperature and allow exploring regions where important magnetic behaviors could arise.