Symmetry breaking at atomic steps of ultrathin Fe films grown on stepped Ag(001) substrates creates a uniaxial magnetic anisotropy with the easy axis parallel to the step edges. The relation between this induced anisotropy and the step density is systematically investigated by magneto-optically scanning films grown on a curved substrate with a vicinal angle range between 0° and 10°. We find that (a) the uniaxial anisotropy depends quadratically on the step density, and (b) the spin-reorientation transition occurs at a larger thickness for the stepped than for the flat film.

• Received 13 May 1996

DOI:https://doi.org/10.1103/PhysRevLett.77.2570