Study of extraordinary phase transition in thin anti-ferromagnetic films: computer simulation

In the article, an extraordinary phase transition in thin antiferromagnetic films was investigated by computer modeling. The simulation uses the Ising model and Metropolis algorithm. Cubic crystal lattice epitaxial films containing multiple monoatomic layers are studied in the paper. The difference in the value for the exchange integrals in the bulk and on the surface of the film is a condition for the appearance of surface and extraordinary phase transitions. The film shall contain at least eight monoatomic layers for appearance of surface and extraordinary phase transitions. The extraordinary phase transition is investigated at different film thicknesses. Magnetic susceptibility demonstrates a logarithmic dependence on Neel temperature near the phase transition point. The dependence of the critical exponent of magnetic susceptibility on film thickness is calculated for the logarithmic phase.