Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)
MA 18.31: Poster
Dienstag, 26. Februar 2008, 15:15–18:30, Poster E
Mößbauer spectroscopy of Fe2−xCo1+xSi Heusler alloys — •Verena Jung, Benjamin Balke, Gerhard H. Fecher, and Claudia Felser — Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, 55099 Mainz
This work reports about the properties of the solid solutions of Fe2−xCo1+xSi Heusler alloys. Generally the X2YZ Heusler compounds crystallise in the cubic L21 structure (space group no. 225: F m3m). The cubic X2YZ compounds are not only found with the AlCu2Mn type structure but also with the CuHg2Ti type structure. This formal XYXZ-type structure exhibits Td symmetry (space group no. 216: F 43m). In that structure the two X atoms occupy non equivalent positions in contrast to the L21 structure. This structure is frequently observed if the nuclear charge of the Y element is larger than the one of the X element from the same period, that is Z(Y)>Z(X) for two 3d transition metals. However, the two structures may be hardly distinguishable by X-ray diffraction as both have the general fcc-like symmetry. Therefore, 57Fe Mößbauer spectroscopy was performed to determine the local environment and hyperfine magnetic fields of the iron atoms. Two different hyperfine magnetic fields were clearly detected due to the two different local environments of the Fe atoms in Fe2−xCo1+xSi Heusler alloys crystallising in the CuHg2Ti type structure.