Surface magnetic properties of an anisotropic free surface in the semi-infinite Ising model

The influence of anisotropy on the phase transitions of a semi-infinite three-dimensional Ising model is investigated by the use of the effective field theory. The surface magnetism is examined as a function of Δ = Jy/J − 1 and α = Jx/Jy, where Jx and Jy are the nearest-neighbor exchange constants in the free surface and J in the volume. The critical values Δc, transition temperatures and phase diagrams for surface ordering are given as functions of α and Δ. The reduced magnetization curves of a surface and bulk are also studied.