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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 63.88: Poster

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

Optical Investigation of Spin Injection from (Ga,Mn)As into n-GaAs — •Bernhard Endres, Matthias Sperl, Martin Utz, Dieter Schuh, Andreas Einwanger, Mariusz Ciorga, Christian Back, and Günther Bayreuther — Universität Regensburg

Spin injection from a Ga(Mn,As) contact into a n-GaAs channel through an Esaki diode structure was investigated. Details of the layer structure are described in Ref 1. After lithographic patterning the spin polarization in the GaAs was measured by p-MOKE at low temperatures across a cleaved edge as described in Ref. 2. From the distribution of the spin polarization below the injecting contact the spin diffusion length and the drift dependent spin decay length can be estimated, which are important parameters for the calculation of the spin lifetime from Hanle-measurements. However, several contributions to the Hanle curves as the stray field, dynamic nuclear polarization and a tilted magnetization of the injector make the calculation of the spin lifetime more complex. In this contribution the different parameters of the sample are characterized by fitting experimental data with a one-dimensional drift-diffusion equation. A spin diffusion length of about 5 μm and a spin lifetime of 10 ns was observed.

[1] M. Ciorga et al., Phys. Rev. B, 79(16):165321 (2009)

[2] P. Kotissek et al., Nature Phys. 3, 872 (2007)