Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 9: Poster I

HL 9.87: Poster

Monday, March 27, 2006, 15:15–17:45, P3

Anisotropic magnetoresistance and planar Hall effect in (100) and (311)A GaMnAs — •Thomas Hummel, Michael Glunk, Joachim Däubler, Wladimir Schoch, Wolfgang Limmer, and Rolf Sauer — Abteilung Halbleiterphysik, Universität Ulm, D-89069 Ulm, Germany

The in-plane longitudinal and Hall resistance (planar Hall effect) of GaMnAs is studied for epitaxial GaMnAs layers grown on (100) and (311)A GaAs substrates. The measurements are carried out at T=4.2K on photolithographically prepared Hall bars with an external magnetic field continuously adjustable in magnitude and orientation. Sweeping the strength of the magnetic field for fixed orientations or stepping its orientation at fixed field strengths results in pronounced jumps of both the longitudinal and Hall resistance due to the magnetic anisotropy of the GaMnAs epilayers. A quantitative analysis of the data within a single domain model reveals that the direction of the magnetization can be significantly deflected from the magnetic easy axes by the external magnetic field even for low field strengths below 50 mT. Specific differences between the (100) and (311)A GaMnAs layers are discussed.