Berlin 2015 – scientific programme

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DS: Fachverband Dünne Schichten

DS 36: Poster Session I

DS 36.39: Poster

Thursday, March 19, 2015, 09:30–12:00, Poster A

Growth and characterisation of epitaxial Mn₅Ge₃C_x films — •Maximilian Kauth¹, Christoph Sürgers¹, and Hilbert v. Löhneysen^{1, 2} — ¹Physikalisches Institut, Karlsruher Institut für Technologie, D-76049 Karlsruhe — ²Institut für Festkörperphysik, Karlsruher Institut für Technologie, D-76021 Karlsruhe

Ferromagnetic Mn₅Ge₃C_x films with Curie temperatures well above room temperature are potential spin-injection materials to be used in CMOS-compatible spintronic devices. Previously sputtered polycrystalline films exhibit a coarse-grain morphology. Alternatively, we have grown [0001]-oriented Mn₅Ge₃C_x (x = 0, 0.8) films on in-situ cleaned Ge(111) substrates by electron-beam evaporation in ultra-high vacuum. The films have been characterised by in-situ high-energy electron diffraction, atomic-force microscopy, x-ray diffraction, and resistivity measurements. Mn₅Ge₃C_x films obtained by solid-state reaction of Mn or codeposited Mn-C layers on Ge(111) at 300 - 450^∘C exhibit a rough surface with holes of sub-micrometer diameter extending down to the substrate. Hole formation can be avoided if Mn, Ge, and C are simultaneously deposited at 300^∘C on a thin Mn₅Ge₃ seed layer on Ge(111). The films show a lower corrugation, lower resistivity, higher residual resistance ratio, and a enhanced Hall coefficient compared to polycrystalline films prepared by magnetron sputtering.