FERRIMAGNETIC ORDERING IN FE3/RUN SUPERLATTICES

The electronic and magnetic properties of Fe/Ru hcp superlattices has been investigated by the self-consistent LMTO method for a constant Fe layer thickness (3 monolayers). The lattice parameters have been deduced from experimental measurements performed by Maurer et al. on epitaxial layers grown by molecular beam epitaxy. It is shown that in all the compounds of this series the paramagnetic state is always the less stable. The ground state results from a competition between ferromagnetic and ferrimagnetic ordering of the Fe monolayers, depending upon the Ru thickness; in these compounds, with rather thin Ru layers, the ferrimagnetic phase is slightly more stable, but the ferromagnetic phase seems to be favored by the increase of the Ru layers thickness.