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HL: Fachverband Halbleiterphysik

HL 61: Poster II: Materials, Interfaces and Heterostructures

HL 61.39: Poster

Donnerstag, 25. März 2010, 18:00–20:00, Poster D1

Suppression of interfacial intermixing of MBE grown Heusler Alloy Ni₂MnIn on (001)InAs — •Sascha Bohse¹, Andriy Zolotaryov¹, Stefan Singer¹, Andreas Volland¹, Dieter Lott², Andrea Stemmann¹, Christian Heyn¹, and Wolfgang Hansen¹ — ¹Universität Hamburg, Institut für Angewandte Physik, Germany — ²GKSS Forschungszentrum, Germany

We study MBE grown Heusler Alloy Ni₂MnIn films on (001)InAs in order to inject spin polarized currents into semiconductor heterostructures. Our previous investigations revealed an optimal growth temperature for deposition of Heusler films on (001)InAs in the favored L2₁ phase at 300^∘C[1]. However, at this temperature a strong interfacial intermixing is found that reduces the quality of the interface. We pursue two promising methods to overcome the intermixing and present first results. Firstly, the application of a thin MgO layer as a diffusion barrier embedded between the substrate and the Heusler film is investigated. The second method is to use at the interface a growth temperature of 80 ^∘C, at which intermixing is negligible, and ramp up the temperature to 300 ^∘C during Heusler film growth. The structural properties of films with thicknesses of 20, 60 and 100 nm are studied with atomic force microscopy (AFM) and X-ray reflectivity measurements (XRR). The composition is analyzed with energy dispersive X-ray spectroscopy (EDX). For magnetization measurements SQUID magnetometry has been used.

[1] A. Zolotaryov et al. , Journal of Crystal Growth 311 (2009) 2397-2404