Regensburg 2010 – wissenschaftliches Programm

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KR: Fachverband Kristallographie

KR 10: Poster: Multiferroics (with MA, DF, KR, DS)

KR 10.73: Poster

Dienstag, 23. März 2010, 10:45–13:45, Poster A

Magnetoresistrance of thin film microstructures of the Heusler compounds Cu₂MnAl and Co₂MnSi — •Mohamed Obaida^1,2, Denise Erb², Kurt Westerholt², and Hartmut Zabel² — ¹Institut für Experimentalphysik 4,Ruhr-Universität Bochum,44780 Bochum — ²National Research Center, Tahrir Street-Dokki., 12311 Cairo., Egypt.

We study the magnetoresistance of thin films of the ferromagnetic Heusler compounds Cu₂MnAl and Co₂MnSi. The Heusler thin films are prepared by UHV magnetron sputtering and shaped into rectangular bars with a width between 1 µm and 50 µm by optical lithography. The magnetoresistance is measured in magnetic fields up to 4 T and for the orientation of the field parallel and perpendicular to the in-plane current. In the as-prepared state the Heusler alloy films are non-ferromagnetic and exhibit a very small magnetoresisitance only. The magnetoresistance strongly increases when the ferromagnetism gradually develops after step by step thermal annealing at high temperatures and decreases again when the magnetic moment approaches its maximum value. The magnetoresistance is dominated by an isotropic spin disorder contribution; only in the state with the maximum magnetic moment an additional small anisotropic magnetoresistance (AMR) can be resolved.