Monte Carlo simulation on magnetic property in triangular Heisenberg system with single-ion anisotropy

Ca₃Co₂O₆ has a rhombohedral structure composed of Co₂O₆ chains running along the hexagonal c-axis, separated by Ca²⁺ ions. Each chain is surrounded by six equally spaced chains, forming a triangular lattice in the ab plane. Because the intra-chain ferromagnetic coupling is much stronger than the inter-chain antiferromagnetic interaction, as T decreases, each ferromagnetic chain would behave like a rigid magnetic moment. Regarding each spin chain as a rigid giant spin, the three-dimensional compound may be simplified into a 2D triangular lattice. Therefore, in the present work, Monte Carlo simulation is performed on a 2D triangular lattice with classical Heisenberg spins. We focus on the influence of single-ion anisotropy to the magnetic property in this system. The results obtained are helpful to understand the stepwise magnetic behavior observed in Ca₃Co₂O₆.