On the Direction of Magnetization in Ferromagnetic Thin Films

Abstract

A microscopical description of the equilibrium direction of the spontaneous magnetization of thin ferromagnetic films is developed, taking into account in the Hamiltonian, besides the exchange term, also the dipolar and the magnetic anisotropy terms. The problem is studied with respect to the film thickness, magnetic anisotropy constant, and temperature. The first order of the Heisenberg's traces method for a free-energy minimization procedure was used. It is stated that the dipolar and anisotropy terms of the Hamiltonian fully determine the direction of the spontaneous magnetization.