Institut für Theoretische Physik, RWTH Aachen, 52056 Aachen, Germany.
J Phys Condens Matter. 2010 Feb 24;22(7):076004. doi: 10.1088/0953-8984/22/7/076004. Epub 2010 Feb 2.
We investigate Ising ferrimagnets on square and simple cubic lattices with exchange couplings between spins of values S = 1/2 and 1 on neighbouring sites and an additional single-site anisotropy term on the S = 1 sites. Mainly on the basis of a careful and comprehensive Monte Carlo study, we conclude that there is no tricritical point in the two-dimensional case, in contradiction to mean-field predictions and recent series results. However, evidence for a tricritical point is found in the three-dimensional case. In addition, a line of compensation points is found for the simple cubic, but not for the square lattice.
我们研究了具有交换耦合的正方形和简单立方晶格上的 Ising 亚铁磁体，相邻格点上的自旋值为 S = 1/2 和 1，而 S = 1 格点上有一个附加的单-site 各向异性项。主要基于仔细和全面的蒙特卡罗研究，我们得出结论，在二维情况下没有临界点，与平均场预测和最近的级数结果相反。然而，在三维情况下发现了临界点的证据。此外，在简单立方晶格中发现了一条补偿点线，但在正方形晶格中没有。
