The critical properties of the Ising model in a magnetic field

The phase transitions and critical properties of the three-dimensional stacked triangular-lattice Ising antiferromagnet in a magnetic field are studied using the replica Monte Carlo method. The nature of the phase transitions is analyzed on the basis of the histogram method. It is established that a second-order transition occurs in the field range of 0 ≤ h ≤ 6. At a high field, the degeneracy of the ground state is lifted and the phase transition is smeared. Depending on the magnitude of the magnetic field, disordered, partially ordered, and completely ordered phases are observed.