Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 13: Poster 1

HL 13.20: Poster

Montag, 26. März 2007, 15:00–17:30, Poster A

Magnetotransport measurements on GaMnAs and on GaMnAs/MnAs hybrid structures — •Matthias Elm¹, Jörg Teubert¹, Wolfram Heimbrodt¹, Peter Jens Klar², Matthias Reinwald³, and Werner Wegscheider³ — ¹Department of Physics and Material Science Center, Philipps-University of Marburg, Germany — ²1. Physics Institute Justus Liebig University of Giessen, Germany — ³Institute of Applied and Experimental Physics II, University of Regensburg, Germany

GaMnAs alloys on (311)A substrate grown by LT-MBE and corresponding GaAs:Mn/MnAs hybrid structures obtained by thermal annealing have been investigated. A controlled thermal annealing of highly Mn doped GaAs layers leads to the formation of MnAs nanocrystals by segregation effects. Increasing annealing temperature leads to increasing cluster size. GaMnAs layers and GaAs:Mn/MnAs hybrids have been studied by magnetotransport for different orientations of the applied external magnetic field. The measurements were performed on Hall-bars with a length of 650 µm and a width of 200 µm in a temperature range from 2 to 280 K in magnetic fields up to 10 Tesla. The transport behaviour of the alloy samples and the hybrids show distinct differences. In contrast to the hybrid structures the alloys show also a clear angle dependence in the transport behaviour. The results were used in order to determine the anisotropic parameters.