Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 4: Surface Magnetism I
MA 4.4: Vortrag
Montag, 23. März 2009, 11:45–12:00, HSZ 403
Magnetic and structural investigations of self-organised iron based nanostructures on GaAs(110) — •Carsten Godde1, Sani Noor1, Athena Rastgoo Lahrood1, Gregor Nowak2, Hartmut Zabel2, and Ulrich Köhler1 — 1Institut für Experimentalphysik IV / AG Oberflächen, Ruhr-Universität Bochum, Germany — 2Institut für Experimentalphysik IV, Ruhr-Universität Bochum, Germany
The structure and the magnetic behaviour of Fe-layers and self-organised iron based nanostructures on GaAs(110) were studied in a UHV system that offers the means for structural analysis by STM and LEED and magnetic characterization by MOKE during deposition. The structure of the Fe-layer when grown at room temperature has a closed granular structure with a magnetic anisotropy depending on the thickness of the Fe-layer. At elevated temperatures a disrupted layer develops. The effect of annealing up to 450∘C on the structure and the magnetic behaviour were studied for two different cases - during and after deposition of the iron layer. The increasing temperature leads to a transformation of the Fe-layer to an array of self-organised ferromagnetic nanostructures for both cases. These nanostructures are roof-shaped 3D-islands elongated along the [110]-direction of the GaAs(110) substrate. STM also shows an indication that Ga and As from the substrate diffuse into the Fe-islands. This intermixing by annealing leads to a ternary alloy Fe3Ga2−xAsx which is proofed by x-ray diffraction. Despite of this alloying magnetic measurements of the nanostructures by MOKE show ferromagnetic characteristics and a correlation between magnetic and structural anisotropy.