Spin reorientation transition in Fe(110) thin films: The role of surface anisotropy

We report on the spin reorientation phase transition in Fe(110) ultrathin films, epitaxially grown on a W(110) single crystal. The critical film thickness of the magnetic reorientation (t(r)) has been monitored by spin-resolved photoemission. Either an increase or a decrease of t(r) can be induced by controlled modification of the surface (anisotropy) of the Fe films. t(r) is reduced by deposition of noble metal (Ag and Au) overlayers on the Fe(110) surface. The effect is significantly more pronounced in the case of Au overlayers than Ag. In contrast, t(r) is found to increase by small amounts of oxygen (0.25 monolayer) adsorbed on the Fe(110) surface.