Regensburg 2007 – scientific programme
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MA: Fachverband Magnetismus
MA 20: Magnetic Thin Films II
MA 20.2: Talk
Wednesday, March 28, 2007, 15:30–15:45, H5
Epitaxial Heusler alloy cobalt iron silicide films on GaAs — •Jens Herfort, Masahiko Hashimoto, Hans-Peter Schönherr, Achim Trampert, and Klaus Ploog — Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin
Heusler alloys are promising candidates for spintronic and magnetotunneling applications due to their high Curie temperatures, compatibility with compound and elemental semiconductors and their possibly half-metallic behavior. However, atomic ordering and interface quality have a significant influence on their structural, electrical and magnetic properties. Here, we present our results on the fabrication as well as the structural, electrical and magnetic properties of single-crystal Co2FeSi/GaAs(001) heterostructures grown by molecular-beam epitaxy at various growth temperature TG. As evidenced by double crystal X-ray diffraction (DCXRD) and transmission electron microscopy (TEM) measurements, ferromagnetic layers with high crystal and interface perfection can be obtained. The exact stoichiometry of the Heusler alloy films can be achieved for almost lattice matched films. From DCXRD, TEM and resistivity measurements we find an optimum TG, near 200∘C, to obtain layers with high crystal and interface perfection as well as high a degree of atomic ordering. It is important to note that this optimum TG is considerably higher than that for Fe and Co on GaAs(001). The layers are ferromagnetic at room temperature with the easy axis of magnetization within the film plane. The dependence of the magnetic in-plane anisotropy on the stoichiometry as well as on the atomic ordering will be addressed.