In situ Brillouin scattering from surface-anisotropy-dominated Damon-Eshbach modes in ultrathin epitaxial Fe(110) layers

Epitaxially grown Fe(110) layers on W(110) with thicknesses between 8 and 150 Å have been investigated in situ by Brillouin scattering. Below 60 Å a so-far-unobserved strong increase of the frequency of the Damon-Eshbach mode by a factor of up to 3 has been found with decreasing layer thickness. This novel behavior is described quantitatively by a model, which takes explicitly into account magnetic surface anisotropies. An additional growth-induced uniaxial magnetic surface anisotropy due to steps in the Fe layer could be identified.