Microscopic Approach to Interfacial Structure in Ising-like Ferromagnets

Abstract

The properties of an Ising-like ferromagnetic model are investigated in the presence of a space-dependent magnetic field which favors phase separation. The treatment is limited to very low temperatures where molecular-field theory seems to be applicable. The magnetization profile in the interface region is calculated, as well as the interface free energy, within an harmonic approximation to magnetization density modes in our model. The instability of the interface in the limit of vanishing external field, which was recently pointed out for fluid systems, is recovered and discussed in detail.