Spin waves in ultrathin Co-films measured by spin polarized electron energy loss spectroscopy

We present spin polarized electron energy loss spectra of ultrathin Co films on Cu(0 0 1), in which spin-wave excitations appear as prominent peaks. The spin-wave dispersion can be measured up to and beyond the surface Brillouin zone boundary. For Co-film thicknesses down to 2.5 monolayers no strong thickness dependence of the spin-wave energies are observed.