Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)
MA 13.122: Poster
Dienstag, 9. März 2004, 15:00–19:00, Bereich A
Thickness dependence of the spin-wave dispersion in ultrathin Co films — •Markus Etzkorn1, P. S. Anil Kumar1, W. Tang1, R. Vollmer1, H. Ibach2, and J. Kirschner1 — 1Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle — 2Institut für Schichten und Grenzflächen ISG3, Forschungszentrum Jülich, 52425 Jülich
We present spin polarized electron energy loss spectra of surface spin waves in ultrathin Co films on Cu(001). Starting from our earlier studies on 8 ML [1] we have explored the influence of reduced thickness on the spin-wave dispersion down to 2,5 ML Co. The measured spin-wave energies can be fitted surprisingly good by a dispersion curve derived from a nearest neighbor Heisenberg model. Our analysis of the dispersion curves indicates that the exchange coupling constant at the Co surface is not significantly enhanced compared to its bulk value, in disagreement with theoretical expectations [2,3]. At the surface Brillioun zone boundary the spin-wave energy is independent of the thickness down to 2,5 ML indicating a rather short range exchange coupling interaction not much beyond the NN distance.
[1] R. Vollmer, M. Etzkorn, P. S. Anil Kumar, H. Ibach, and J. Kirschner, Phys. Rev. Lett. 91 (2003) 147201.
[2] M. Pajda, J. Kudrnovský, I. Turek, V. Drchal, and P. Bruno, Phys. Rev. Lett. 85 (2000) 5424.
[3] S. S. A. Razee, J. B. Staunton, L. Szunyogh, and B. L. Györffy, Phys. Rev. B 66 (2002) 094415.