Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 36: Micro- and Nanostructured Magnetic Materials III
MA 36.5: Vortrag
Mittwoch, 16. März 2011, 15:45–16:00, HSZ 103
Influence of MnAs nanoclusters on the angle-dependent transport behaviour in GaAs:Mn/MnAs hybrid structures — •Matthias T. Elm1, Shingo Ito2, Shinjiro Hara2, Hans-Albrecht Krug von Nidda3, and Peter J. Klar1 — 11. Physikalisches Institut, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392 Gießen — 2Research Center for Integrated Quantum Electronics, Hokkaido University, Sapporo, Japan — 3Experimentalphysik V, University of Augsburg
Using selective-area MOVPE on pre-patterned substrates different arrangements of ferromagnetic MnAs nanoclusters and cluster chains were prepared. The single nanoclusters have a length of 730 nm and a width of 300 nm. FMR and MFM measurements confirm an orientation of the cluster magnetization along the clusters’ main axes of elongation. Magneto-transport measurements were performed in the temperature range from 15 to 280 K in external magnetic fields up to 10 T. A strong dependence of the magnetoresistance effects on cluster arrangement can be observed. At low temperatures also angle-dependent measurements of the transport through the paramagnetic matrix were investigated. In-plane as well as in out-of-plane geometry the magnetoresistance behaviour shows deviations from an expected sine-dependence of the matrix. This behaviour can be described qualitatively by a simple model taking an average behaviour of the nanoclusters’ magnetizations into account.