Berlin 2005 – scientific programme
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MA: Magnetismus
MA 8: Spindynamik I
MA 8.1: Talk
Friday, March 4, 2005, 15:15–15:30, TU H1028
High wave vector spin waves in ultrathin hcp Co-films on W(110) — •M. Etzkorn1, P. S. Anil Kumar1, W. Tang1, R. Vollmer1, Y. Zhang1, H. Ibach2, and J. Kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle — 2Institut für Schichten und Grenzflächen ISG3, Forschungszentrum Jülich, 52415 Jülich
We present spin-polarized electron energy loss spectroscopy (SPEELS) measurements of high wave vector spin waves in ultrathin hcp Co-films on W(110) and compare the results to results obtained on fcc Co on Cu(001) [1]. In general, in both systems the spin-wave excitations show similar behaviour. A surprisingly good agreement was found between the measured dispersion of hcp and fcc Co and the dispersion of a surface spin wave in a nearest neighbor Heisenberg model. For both systems the product of the exchange coupling constant and the magnetic moment is JS = 15 meV within the experimental error. The spin-wave dispersion measured on thin, hcp Co-films by SPEELS is also compared to results of inelastic neutron scattering experiments performed on bulk hcp Co [2]. A moderate reduction of JS was found for the thin films.
The intensity of the spin-wave loss feature in the SPEEL- spectra strongly depends on the kinetic energy of the scattering electrons. High spin-wave intensities are only observed for incoming electron energies below about 10 eV.
[1] R. Vollmer, M. Etzkorn, P. S. Anil Kumar, H. Ibach and J. Kirschner, Phys. Rev. Lett. 91 (2004) 147201. [2] T. G. Perring, A. D. Taylor and G. L. Squires, Physica B 213&214 (1995) 348.