The effects of nearest- and next-nearest neighbor interactions on the magnetic properties of films with BCC structure

Abstract An improved 4×4 transfer matrix (TM) method is developed. Based on Monte Carlo (MC) simulation and TM method, the effects of nearest- and next-nearest neighbor (NN, NNN) interactions on the magnetic properties of films with body-centered cubic structure are studied. The phase diagrams describing the phase transition temperature of the surface and inner layers are derived and the surface and size effects are also investigated. The simulated results by Monte Carlo method are in good agreement with those derived by mean field theory with the 4×4 transfer matrix, and can well explain the experimental facts.