The ±J±J model for the mixed-spin 1/2 and 3/2 Blume–Capel model

The effects of the bimodal bilinear exchange interaction, ±J±J model, are investigated for the mixed-spin 1/2 and 3/2 Blume–Capel (BC) model on the Bethe lattice (BL). The bilinear exchange interaction is either turned on ferrimagnetically (J>0)(J>0) or turned off antiferrimagnetically (J<0)(J<0) with probabilities p   and 1−p1−p for the nearest-neighbor sites on the BL. The phase diagrams of the model are obtained with the inclusion of the crystal field interactions on the sites of spin-3/2 for the coordination number, q=3,4 and 6, for given p values. It was found that the model gives either second- or first-order phase transition lines for each given value of p. The temperatures of these lines increase with the increasing values of q.