Blume-Emery-Griffiths model for mixed spin (1,5/2) calculated by mean-field approximation

We use the mean-field approximation based on the Bogoliubov inequality to study the ferrimagnetic mixed spin-1 and spin-5/2 Blume-Emery-Griffiths (BEG) model on a hypercube lattice. The effects of the equal crystal field D = D-A = D-B and the ratio of biquadratic and bilinear exchange interactions R = K/|J| are examined by extracting the phase diagrams on the (R = K/|J|; T = 1/z|J|) and (D/z|J|; T = 1/z|J|) planes, respectively. Additionally, we have drawn the phase diagrams in the (D-A/z|J|; T = 1/z|J|) and (D-B/z|J|; T = 1/z|J|) planes for various values of the ratio R = K/|J| (R > 0). Our phase diagrams show both first- and second-order transitions, as well as tricritical points. It is evident that the system can exhibit single and double compensation temperatures. Finally, the temperature dependencies of the total and sublattice magnetizations present a few outstanding features.Graphical abstractPhase diagrams and magnetization curves for some physical system parameters

Automated summary

In this study, the mean-field approximation based on the Bogoliubov inequality is used to investigate the ferrimagnetic mixed spin-1 and spin-5/2 Blume-Emery-Griffiths (BEG) model on a hypercube lattice. The phase diagrams and the temperature dependencies of magnetization are analyzed to understand the effects of crystal field and exchange interactions. The results show various phase transitions and compensation temperatures, indicating the complexity of the system's magnetic properties.