Magnetic properties and phase diagrams of the spin-1 Ashkin Teller model ferromagnetic thin films in the presence of a crystal field

Abstract

Using Monte Carlo simulations based on the Metropolis algorithm, we have investigated magnetic properties and phase diagrams of the spin-1 Ashkin Teller model ferromagnetic thin films. The effects of the crystal field D/J2b and four-spin coupling (J4s/J2b, J4b/J2b) has been studied in detail. Therefore, the phase diagrams in the (kBTc/J2b,J2s/J2b) plane exhibits the special point (Rs=J2s/J2b)sp, for different values of D/J2b and (J4s/J2b, J4b/J2b), wherein all film thicknesses having the same critical temperature. In addition, the magnetization profiles present a first order phase transition behavior. Then, we found rich phase diagrams with first- and second-order phase transitions that meet at tricritical points that are dependent on the film thickness N. Finally, this model presents a new partially ordered phase 〈σS〉, between the paramagnetic phase and the Baxter phase, which are separated by a second-order phase transition, for positive values of D/J2b and for each film thickness N.