Electronic, magnetic, and structural properties of the Fe/ZnSe interface

The electronic, magnetic, and structural properties of Fe thin films epitaxially grown on ZnSe(001) have been investigated by spin polarized inverse photoemission, x-ray photoemission, magneto-optical Kerr effect, and scanning tunneling microscopy. Ultrathin Fe films present no magnetic remanence, while ferromagnetism develops for Fe coverage larger than 7 ML. However, even in this case, the electronic structure of empty states is quite different from that of high quality Fe(001) films. These findings are interpreted in terms of an evolution from a low coverage superparamagnetic phase towards a ferromagnetic phase typical of thicker films, whose electronic properties still remain different from those of ideal Fe(001) films. The consequences for spin-dependent transport across the Fe/ZnSe(001) interface are discussed.