Suppression of Standing Spin Waves in Low-Dimensional Ferromagnets
  We examine the experimental absence of standing spin wave modes in thin magnetic films, by means of atomistic spin dynamics simulations. Using Co on Cu(001) as a model system, we demonstrate that by increasing the number of layers, the "optical" branches predicted from adiabatic first-principles calculations are strongly suppressed, in agreement with spin-polarized electron energy loss spectroscopy measurements reported in the literature. Our results suggest that a dynamical analysis of the Heisenberg model is sufficient in order to capture the strong damping of the standing modes. 
Andrea Taroni, Anders Bergman, Lars Bergqvist, Johan Hellsvik and Olle   Eriksson
cond-mat.mtrl-sci