A mean-field study of the temperature dependence of the layer magnetizations in a semi-infinite ising model

Summary We present a mean-field study of the layer magnetization of a semi-infinite Ising model with intra-surfaceJ _B and surface-bulkJ ₁ interaction modified with respect to the bulk exchange interactionJ. This allows to discuss the extent of the spatial inhomogeneity perpendicular to a free surface. By following the magnetization of each layer, we are able to see how the critical exponents evolve from the bulk to the surface values. Furthermore, we introduce a new characteristic temperature,T _em, where the surface magnetization departs from the bulk behaviour, as a possible candidate for the experimental determination ofJ ₈ andJ ₁. In honour of Prof. Fausto Fumi on the occasion of his retirement from teaching.