Temperature dependence of the magnetic susceptibility of the spin 1/2 antiferromagnetic XXZ model on a square lattice

The magnetic susceptibility of the XXZ model is studied over a wide temperature range by the Green's function method with the Kondo-Yamaji decoupling scheme. By this method it is possible that both XY- and Ising-like systems are studied in a unified way. In the XY-like system, our results of the transverse uniform susceptibility agree with those of a Monte-Carlo simulation. In the Ising-like system, our temperature dependence of the longitudinal uniform susceptibility agrees well with the experimental results of the susceptibility of quasi-2D Ising-Like antiferromagnet K2CoF4 above its Neel point.