SKM 2023 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 8: Thin Film Properties III
DS 8.2: Vortrag
Dienstag, 28. März 2023, 11:45–12:00, SCH A 315
α-FeGe2 films on GaAs(001) substrates grown by MBE and solid-phase epitaxy — •Moritz Hansemann, Michael Hanke, Achim Trampert, and Jens Herfort — Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany
Layered magnets show promising results towards advancements in the field of spintronics. Such materials exhibiting a ferro- and/or antiferromagnetic (FM/AFM) phases close to room temperature are especially on demand for future technologies.
Recently we discovered a novel metastable α-FeGe2 phase sandwiched between two ferromagnetic Fe3Si Heusler alloy metals. Comprehensive transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements revealed the layered structure and P4mm spacegroup, that is absent in bulk FeGe2. By a combination of molecular beam and solid phase epitaxy we demonstrate the isolated growth of α-FeGe2 on a GaAs(001) substrate. This is achieved by first growing Fe3Si and covering it with amorphous Germanium in the thickness ratio of 1:3. Finally, a subsequent annealing forms the layered FeGe2. Through a optimization of this process we are able to grow layers of extremely high quality with layer thicknesses down to 4 nm. The films are structurally characterized by atomic force microscopy, XRD, X-ray reflectivity and TEM measurements, which also demonstrate the importance of a smooth GaAs initial surface. First transport measurements showed metallic behavior and a ferromagnetic behavior at low temperatures.