Magnetic and thermodynamic properties of the antiferromagnetic Ising model on a layered triangular lattice in a magnetic field

The magnetic and thermodynamic properties of the three-dimensional antiferromagnetic Ising model on a layered triangular lattice with first- and second-nearest neighbor interactions are studied on the basis of the replica Monte Carlo algorithm. The magnetic structures of the ground state in an external magnetic field in the interval 0 ≤ h ≤ 18 are yielded. A disordered, partially ordered, and fully ordered phases are found to occur in the field value range considered. It is shown that the magnetic structures of the ground state and thermodynamic properties depend on the sign of (ferromagnetic (J2 > 0) and antiferromagnetic (J2 < 0)) exchange interactions of the second neighbors. On the magnetization vs magnetic field curve, we find a plateau equal to 1/3 of the saturation magnetization for J2 > 0, and a plateau equal to 1/2 of the saturation magnetization for J2 < 0.