Bond Dilution Effects on Bethe Lattice the Spin-1 Blume–Capel Model

Abstract

The bond dilution effects are investigated for the spin-1 Blume–Capel model on the Bethe lattice by using the exact recursion relations. The bilinear interaction parameter is either turned on ferromagnetically with probability p or turned off with probability 1 – p between the nearest-neighbor spins. The thermal variations of the order-parameters are studied in detail to obtain the phase diagrams on the possible planes spanned by the temperature (T), probability (p) and crystal field (D) for the coordination numbers q = 3, 4, and 6. The lines of the second-order phase transitions, Tc-lines, combined with the first-order ones, Tt-lines, at the tricritical points (TCP) are always found for any p and q on the (T, D)-planes. It is also found that the model gives only Tc-lines, Tc-lines combined with the Tt-lines at the TCP’s and only Tt-lines with the consecutively decreasing values of D on the (T, p)-planes for all q.