Wetting and Layering Transitions in a Nano-Square Structure: Monte Carlo Study

In this work, we study the magnetic wetting and layering transitions in a nano-square structure. The system is consisting of particles with spins s= 1/2 and S=1 placed at the square sites. We study the effect of the exchange couplings between different spins, namely, s- s, S- s, and S-S. The wetting phenomena and layering transitions are found under the effect of the temperature and the external magnetic field, for fixed values of the exchange coupling parameters. When studying the temperature effect on the magnetizations, using Monte Carlo simulations, the ground-state phase diagrams confirm these results for very low temperatures. Over the 2 × 2 × 2 × 3 = 24 possible configurations, only 6 configurations are found to be stable in the ground-state phase diagrams. Though the model established equations are valid for any system sizes, we give results and numerical values for a fixed system size formed only by four square layers.