The bond mixed spin-1 Ising model

Using the one-spin cluster approximation we have studied the temperature dependence of the magnetization and the quadrupolar moment for the spin-1 Ising model on a square lattice. Nearest-neighbour ferromagnetic exchange interactions J with concentration p and exchange interactions αJ (¦α¦ ≤ 1) with concentration (1 − p) have been considered. Differences for re-entrant and non re-entrant behaviour are shown.