DEPENDENCE OF MAGNETIC SURFACE ANISOTROPIES ON SYMMETRIES OF A NONMAGNETIC OVERLAYER

Au(111) grows on Fe(110) in two different orientations depending on the temperature of the substrate. At room temperature it grows in the Nishiyama-Wassermann (NW) orientation, i.e. [110BAR]Au parallel to [001]Fe, whereas above 500 K the Kurdjumov-Sachs (KS) orientation, [110BAR]Au parallel to [111]Fe, is preferred. Annealing a film in the metastable NW-orientation causes an irreversible reconstruction into the KS-orientation. These different orientations are shown to exhibit different magnetic surface anisotropies in Fe-films grown on W(110). The Au/Fe(110)-interface in KS-orientation shows roughly the same comparatively small in-plane anisotropy with an energy minimum along the [110BAR]Fe-direction, as the uncoated surface. Contrarily, the NW-orientation results in a strong anisotropy with a minimum in the [001]Fe-direction.