A Monte Carlo study of thin spin-1 Ising films with surface exchange enhancement

Using extensive Monte Carlo simulations the effect of surface exchange enhancement on ultrathin spin-1 Ising films (having simple cubic symmetry) ranging in thickness from L=3 to 8 atomic layers, has been studied. The simulations were performed on systems containing up to just over 15000 spins with periodic boundary conditions imposed in directions perpendicular to the film thickness. Within the resolution of the Monte Carlo data, it was concluded that the ratio of surface to bulk exchange interaction strengths, Js/Jb)crit, at which the critical temperatures of the film and bulk material were equal, was independent of L, as predicted by mean field and effective field theories. However, the value of Js/Jb)crit is spin dependent. It was found that for the spin-1 Ising films, Js/Jb)crit=1.45, significantly below the value 1.52 obtained by Monte Carlo simulation for the spin ((1)/(2)) system reported in the literature