Dresden 2011 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 63: Poster II (Surface Magnetism/ Magnetic Imaging/ Topological Insulators/ Spin Structures and Magnetic Phase Transitions/ Graphene/ Magnetic Thin Films/ Magnetic Semiconductors/ Magnetic Half-metals and Oxides/ Spin-dependent Transport/ Spin Excitations and Spin Torque/ Spin Injection and Spin Currents in Heterostructures/ Spintronics/ Magnetic Storage and Applications)

MA 63.27: Poster

Freitag, 18. März 2011, 11:00–14:00, P2

Ferrimagnetism and disorder in epitaxial (Mn_1−xCo_x)₂VAl thin films — •Markus Meinert¹, Jan-Michael Schmalhorst¹, Günter Reiss¹, and Elke Arenholz² — ¹Dünne Schichten und Physik der Nanostrukturen, Fakultät für Physik, Universität Bielefeld, 33501 Bielefeld, Deutschland — ²Advanced Light Source, Lawrence Berkeley National Laboratory, CA 94720, USA

Thin films of the quarternary full Heusler compound (Mn_1−xCo_x)₂VAl were prepared by DC and RF magnetron co-sputtering on heated MgO (001) substrates. The magnetic structure was examined by x-ray magnetic circular dichroism and the chemical disorder was characterized by x-ray diffraction. For x=0.5 a full compensation of the magnetic moments is expected according to the Slater-Pauling rule m = N_V − 24. Ferrimagnetic coupling of V to Mn was observed for Mn₂VAl (x=0) and x=0.25. For x=0.25, we also found ferrimagnetic order with V and Co antiparallel to Mn. The experimental results are interpreted with the help of band structure calculations. The total magnetic moment is strongly reduced in Mn₂VAl because of preferential D0₃-like Mn-Al disorder. Co₂VAl is only B2 ordered and has reduced magnetization. In the cases with x≥0.45 conventional ferromagnetism was observed, closely related to the atomic disorder in these compounds.