Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 4: Magnetic Materials I

MA 4.3: Vortrag

Montag, 27. März 2006, 10:45–11:00, HSZ 401

Structural and physical properties of the quarternary Heusler alloys Co₂Mn_1−xFe_xSi: A search for the optimal material for spintronic devices — •Benjamin Balke, Hem Chandra Kandpal, Vadim Ksenofontov, Gerhard H. Fecher, and Claudia Felser — Johannes Gutenberg - Universität, 55099 Mainz, Germany

The strucural and magnetic properties of the quarternary Heusler alloys Co₂Mn_1−xFe_xSi (x=0, 0.1,…,1) were investigated by means of X-ray diffraction, SQUID magnetometry, ESCA, ⁵⁷Fe Mößbauer spectroscopy, and differential scanning calometry messurments. The pure Co₂MnSi compound is allready used as an electrode in magnetic tunnel juctions. Previous LSDA calculations predicted Co₂MnSi to be a half-metallic ferromagnet with a spinpolarisation of 100%, a value that could not be verified by experiments up to now. Recent investigations of the electronic strucutre of Heusler compounds gave advice that on-site correlation plays a role in these componds and may serve to destroy the half-metallic properties of Co₂MnSi. At the same time Co₂FeSi becomes a half-metallic ferromagnet if on-site correlation is respected in electronic structure calculations.

This investigation focuses on the search of a mixed compond where the half-metallic behaviour is stable against the variation of on-site correlation. (This work is funded by the DFG in FG 559.)