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 18.32: Poster

Dienstag, 26. Februar 2008, 15:15–18:30, Poster E

Metallurgical Investigations of the Crystal Growth of Co₂FeAl_1−xSi_x Heusler Compounds — •Christian G. F. Blum¹, Benjamin Balke¹, Sabine Wurmehl², Gerhard H. Fecher¹, Claudia Felser¹, and Armin Reller³ — ¹Johannes Gutenberg - Universität, 55099 Mainz — ²Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands — ³Universität Augsburg, 86135 Augsburg

The structure of the crystallites of Co₂FeAl_1−xSi_x Heusler compounds with 0 ≤ x ≤ 1 were investigated. The influence of the annealing process on the crystallisation was studied by annealing the samples for 1-3 weeks at 873-1273 K. Discs were cut from the bulk samples resulting in surfaces with different orientation compared to the direction of the cooling gradient. After polishing, the surfaces of the discs were etched with different acids in order to colour different crystallites differently. The best results were obtained with a solution of 2 mol/L Fe₂Cl₃ in 12% to 8% concentrated HCl. This particular concentrations tinted different crystallites in a different tone while the surface of the sample was not destroyed very deep. Using this approach, different types of crystallites were found: needle-like ones for the Si-rich compounds and block-like for the Al-rich compounds.

The authors gratefully acknowledge financial support by the DFG (Research Unit 559).