Strong magnetic surface anisotropy of ultrathin Fe on curved Pt(111)

We investigate the step decoration growth and magnetic properties of Fe grown on a curved Pt(111) single crystal by means of low-energy electron diffraction, scanning tunneling microscopy, and the surface magneto-optical Kerr effect. We find that the step-induced magnetic anisotropy enhances the Curie temperature of Fe ultrathin films. Fe grown on high-vicinal-angle surfaces has larger values of both the saturation magnetization M-s and coercivity H-c compared with the flat surface. M-s(alpha) increases quadratically with the vicinal angle alpha. The atomic steps of the vicinal surface greatly affect the magnetic properties of ultrathin Fe films. Finally we find that the step-induced surface anisotropy K-s(alpha) is proportional to alpha(4). The surface anisotropy of Fe on curved Pt(111) substrate is related to the numbers of atoms at the step edges and the polarization of proximal Pt atoms.