Fluctuation-induced tetracritical point in the magnetic phase diagram of a quasi-two-dimensional XY antiferromagnet

Abstract

Monte Carlo simulation results of the classical antiferromagnetic planar model on a stacked triangular lattice with weak interplanar exchange coupling, and an in‐plane applied magnetic field, are reported. The determined field‐temperature phase diagram differs significantly from the corresponding mean‐field result and shows that tetracritical behavior occurs at H=0, T=T N , similar to that found previously for the cases of isotropic and quasi‐one‐dimensional magnetic interactions.