Computer Simulation of Surface Phase Transitions of Antiferromagnetic Films

Abstract

The article gives a research of surface phase transitions in thin films described by the Ising antiferromagnetic model by Monte Carlo computer simulation. The simulation is carried out at different values of exchange integrals proportion on the surface and in the bulk of the system. The difference between the exchange integral of interaction between the surface spins and the first subsurface layer from the bulk value is also taken into account. It is shown that the phase diagram of the system has a phase where the ordering of spins on the surface of the system occurs at temperatures below the Neel temperature. The difference between the temperatures of the surface phase transition from the temperature of the bulk phase transition is greater than in semi-infinite systems. This difference is explained by the lower influence of bulk ordering on surface ordering.