Berlin 2008 – scientific programme
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MA: Fachverband Magnetismus
MA 14: Magnetic Half Metals and Oxides
MA 14.9: Talk
Tuesday, February 26, 2008, 12:30–12:45, EB 202
Influence of MBE growth rate on the structural and magnetic properties of epitaxial NiMnSb layers — •Florian Lochner, Peter Bach, Charles Gould, Christian Kumpf, Georg Schmidt, and Laurens W. Molenkamp — Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
NiMnSb is a promising material for application in future spintronic devices because of its
expected half-metallicity and the high Curie temperature of 730 K. In addition, NiMnSb crystallizes in the
C1b structure [1] which is compatible to various Zincblende-type III/V semiconductors. We have shown
previously that high quality NiMnSb layers can be deposited on (In,Ga)As buffer layers by molecular beam
epitaxy [2]. Here we demonstrate that lowering the growth rate from 0.2178 Å/s to 0.0442 Å/s leads to
changes in the structural and magnetic properties of the NiMnSb layers. While the interface flatness is
reduced, as can be inferred from X-ray diffraction, the line width in ferromagnetic resonance (FMR)
decreases, indicating a low damping and high magnetic quality. We will show results of samples deposited on
(001) and (111) oriented InP substrates with a thin (In,Ga)As buffer which is almost lattice matched to the
NiMnSb. The growth process and structural properties (including relaxation dynamics) are characterized by
RHEED patterns and HRXRD measurements, respectively. The magnetic properties are investigated by MOKE and
FMR. We acknowledge the support of the EU project Dynamax.
[1] R.A. de Groot et al., Phys. Rev. Lett. 50 (1983) 2024
[2] Peter Bach et al., J. Cryst. Growth 251 (2003) 323-326