SURFACE MAGNETIC-PROPERTIES OF AN ANISOTROPIC FREE-SURFACE IN THE SEMIINFINITE 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 DELTA = J(y)/J - 1 and alpha = J(x)/J(y), where J(x) and J(y), are the nearest-neighbour exchange constants in the free surface and J in the volume. The critical values DELTA(c), transition temperatures and phase diagrams for surface ordering are given as functions of alpha and DELTA. The reduced magnetization curves of a surface and bulk are also studied.