Transverse ordering of an antiferromagnet in a field with oblique angle to the easy axis

Motivated by the recent experimental observations [Phys. Rev. B 57, R11 051 (1998)] of transverse spin ordering in ${\mathrm{FeBr}}_2$ induced by a magnetic field with oblique angle to the easy axis of the system, we performed extensive Monte Carlo simulations of a classical anisotropic Heisenberg model. We have calculated the specific heat and the parallel and perpendicular components of the magnetization as well as the antiferromagnetic order parameter and studied these quantities as a function of temperature. A tilted spin-flop phase is obtained for certain parameter values. Many of the effects occurring in connection with this phase agree qualitatively well with the experimental facts.