Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 13: Poster Ia: Electron Theory (1); Magnetic Imaging (2,3); Thin Films (4-25); MSMA (26-33); Magn. Semiconductors (34-42); Magn. Half Metals and Oxides (43-60)

MA 13.16: Poster

Dienstag, 24. März 2009, 10:15–13:00, P1A

Magnetic and structural properties of epitaxial thin films of the Heusler compounds Cu₂MnAl and Co₂MnGe — •Denise Erb, Jörg Dudek, Frank Brüssing, Gregor Nowak, Kurt Westerholt, and Hartmut Zabel — Ruhr-Universität Bochum Experimentalphysik IV / Festkörperphysik, Bochum, Deutschland

Several Heusler compounds possess half metallic properties in the ordered L2₁ structure, which make them promising candidates for spintronic applications. We have grown thin films of the Heusler phases Co₂MnGe and Cu₂MnAl using ion beam sputtering and UHV magnetron sputtering on MgO(100) and sapphire a-plane substrates. The structural properties were studied by x-ray diffraction and x-ray reflectivity. Epitaxial thin films with smooth surfaces can be prepared with the substrates at room temperature. The Co₂MnGe film prepared on Al₂O₃ a-plane and a 2nm V seed layer exhibits 12 well defined peaks in the in-plane rocking scan of the (022)-Bragg reflection, indicative of the growth of 3 different crystalline domains rotated by 30^∘ relative to each other. The Heusler phase Cu₂MnAl is actually not half metallic, but exhibits model type behaviour concerning the relations between the structural and magnetic properties. It can be grown on MgO(001) with the in-plane [100]-direction rotated by 45^∘ from the MgO [100]-direction. In the as-grown state the Cu₂MnAl film is non magnetic, ferromagnetic order starts developing when annealing above 280^∘C. The increasing ferromagnetic magnetization is accompanied by an increasing intensity of the (002) superstructure Bragg reflection.
The authors thank the DFG for financial support within the SFB 491.