Critical properties of the two-dimensional planar spin model in the presence of p-fold random anisotropy

Abstract

The two-dimensional planar spin model in the presence of p-fold random anisotropy has been investigated using Monte Carlo simulation and finite size scaling. The system has been examined for p=2, 3, 4, 5, 6 and lattice sizes N=42, 82, 162. The critical behaviour is found to depend on the value of p and is of two types. For p=3, 5, 6 the results indicate a transition to a quasiferromagnetic state at the same temperature as the pure system. At lower temperatures there is evidence for a second transition; however, the system remains quasiferromagnetic. For p=2, 4 the behaviour is different and results suggest a second-order transition to a spin glass phase and no quasiferromagnetism.