Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Spin controlled transport I

HL 25.3: Talk

Tuesday, February 26, 2008, 14:45–15:00, EW 202

Strain-dependent magnetic anisotropy in GaMnAs on InGaAs templates — •Joachim Däubler, Michael Glunk, Stephan Schwaiger, Lukas Dreher, Wladimir Schoch, Rolf Sauer, and Wolfgang Limmer — Institut für Halbleiterphysik, Universität Ulm, 89069 Ulm

We have systematically studied the influence of strain on the magnetic anisotropy of GaMnAs by means of HRXRD reciprocal space mapping and angle-dependent magnetotransport. For this purpose, a series of GaMnAs layers with Mn contents of ∼5% was grown by low-temperature MBE on relaxed InGaAs/GaAs templates with different In concentrations, enabling us to vary the strain in the GaMnAs layers continuously from tensile to compressive, including the unstrained state. Considering both, as-grown and annealed samples, the anisotropy parameter describing the uniaxial out-of-plane magnetic anisotropy has been found to vary linearly with hole density and strain. As a consequence, the out-of-plane direction gradually undergoes a transition from a magnetic hard axis to a magnetic easy axis from compressive to tensile strain. The experimental results are quantitatively compared with theoretical calculations based on the Zener mean-field model proposed by T. Dietl et al. [Phys. Rev. B 64, 195205 (2001)].