Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 4: Magnetic Materials I

MA 4.4: Vortrag

Montag, 27. März 2006, 11:00–11:15, HSZ 401

Structural properties of the quaternary Heusler alloy Co₂Cr_1−xFe_xAl. — •Jonder Morais¹, Sabine Wurmehl², Maria do Carmo M. Alves¹, Sergio R. Teixeira¹, Giovanna Machado¹, Vadim Ksenofontov², Gerhard H. Fecher², and Claudia Felser² — ¹Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brazil — ²Johannes Gutenberg - Universität, 55099 Mainz, Germany

The structural and chemical properties of the Heusler alloy Co₂Cr_1−xFe_xAl (x=0, 0.4, and 1) were investigated comparing powder and bulk samples. The long range order was determined by means of X-ray diffraction and neutron diffraction, while the site specific (short range) order was proved by the extended X-ray absorption fine structure method (EXAFS). The magnetic structure was determined by means of ⁵⁷Fe Mößbauer spectroscopy in transmission mode as well as in X-ray scattering mode in order to compare powder and bulk properties. The chemical composition was analysed by means of X-ray photo emission spectroscopy (XPS) combined with Auger electron spectroscopy (AES) depth profiling. The results from these methods are compared explain the differences between surface and bulk properties and the appearance of disorder in such alloys. (This work is funded by the DFG in FG 559.)