ELECTRONIC-STRUCTURE OF HEXAGONAL IRON LAYERS

Using a tight-binding Hamiltonian, the recursion method and a self-consistent Stoner criterion to calculate the magnetic moments we have investigated the magnetism of 6 hexagonal layers of Fe between ruthenium layers on each sides. With ferromagnetic spin-polarization we obtain a magnetic moment of about 2-mu-B per atom in the 4 inner iron layers and one dead magnetic iron layer at the interface, but the densities of states of this layer shows an antiferromagnetic tendency. Allowing a reverse polarization of the interface layer, a magnetic moment of 1.7-mu-B is obtained for this layer. The two dead layers found experimentally by M. Maurer et al. and C. Liu and S.D. Bader may be related to interface defects such as substitutional Ru atoms or steps.