Dresden 2011 – scientific programme

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KR: Fachgruppe Kristallographie

KR 5: Poster Multiferroics (Joint Session of MA, DF, DS, KR, TT)

KR 5.64: Poster

Tuesday, March 15, 2011, 10:45–13:00, P2

Local epitaxial growth of magnetic shape memory films Ni2MnGa on MgO-buffered CMOS substrates — •Yuansu Luo, Xueyuan Zhang, and Konrad Samwer — I. Phys. Institut, Universität Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen

Local epitaxial films Ni2MnGa were prepared on MgO-buffered CMOS substrates for possible integration of microsensors. The MgO buffer layers were reactively sputtered at 350-700°C, exhibiting a perfect [100] orientation perpendicular to the substrate and accordingly a preference of [010] and [001] orientations parallel to the substrate. No significant difference was found of MgO buffer layers on Si and SiO2. Similar texture behaviours were measured in austenitic Ni2MnGa films and indicate the local epitaxial growth on MgO buffer. The surface of martensitic films reveals thus twin boundaries in two preferred directions perpendicular to each other. The magnetic transition at TC of about 375K was observed relatively sharp, but the martensitic phase transformation (TM ~320K) slightly broad compared to overall epitaxial films prepared on MgO substrates. Two-dimensional (2D) grain growth and thus a smooth surface are typical characters for the local epitaxial films on the MgO buffer, rather than rough 3D grain films prepared directly on SiO2 substrates. (Supported by BMBF-project 13N10061 MSM-Sens)