Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 15: Magnetische dünne Schichten I
MA 15.4: Vortrag
Mittwoch, 10. März 2004, 16:00–16:15, H10
Thermal spin excitations in epitaxial ultrathin Fe films on Au(001) — •W. Kipferl, M. Dumm, M. Sperl, and G. Bayreuther — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstr. 31, 93040 Regensburg
Epitaxial ultrathin Fe films were grown on epitaxial Au surfaces by molecular beam epitaxy. Epitaxial growth was achieved by using an Fe seed layer and a Ag buffer layer on a GaAs(001) substrate. Epitaxial quality and surface structure were verified in situ by RHEED and STM. The magnetic properties of the samples were investigated by MOKE, AGM and SQUID magnetometry between 10 and 350 K. All films have a four-fold anisotropy with the easy axis along [110] below a thickness of 7 monolayers (ML) and along [100] for films thicker than 7 ML 1. The temperature dependence of the spontaneous magnetization for T < 0.5 TC can be well described by Bloch’s law, M(T) = M(0) × (1 − B T3/2), for all samples. With decreasing film thickness the spin wave parameter B increases significantly compared to the bulk. Fe/Au(001) shows a dominating four-fold anisotropy, while in Fe films on GaAs(001) 2 for the thinnest films the magnetic behaviour is governed by a strong uniaxial anisotropy. Thus, the comparison allows us to study the influence of the intrinsic anisotropy on the spin excitations.
Support by the Deutsche Forschungsgemeinschaft (DFG) is gratefully
acknowledged (Grant No. FOR 370).
References:
1 M. Brockmann et al., J. Appl. Phys. 81, 5047 (1997)
2 W. Kipferl et al., J. Appl. Phys. 93, 7601 (2003)