Critical properties of two-dimensional spin s Ising systems with lattice anisotropy

Abstract

A phenomenological renormalisation transformation is used to calculate critical properties of two-dimensional spin s Ising systems with lattice anisotropy. Systems with s=1/2, 1, 3/2, 2, 5/2 are considered for a large range of ratios, R=Ky/Kx, of exchange constants in the x and y spatial directions. Agreement with the exact solution for s=1/2 is good, with the percentage error in Tc becoming very small as R approaches zero. The results for nu are consistent with universality arguments. The estimates of the critical curves suggest an asymptotic form, as R to 0, of Ky approximately 2s exp(-2Kx).