Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 9: Poster 1

HL 9.40: Poster

Monday, March 23, 2009, 14:30–17:00, P2

Magnetooptics of Gd-doped GaN — •Jan Heye Buss, Jörg Rudolph, and Daniel Hägele — AG Spektroskopie der kondensierten Materie, Ruhr Universität Bochum, Germany

SQUID measurements of Gd-doped GaN showed Curie-temperatures up to 700 K [1]. GaN:Gd is therefore discussed as a potential electron spin aligner for room temperature spintronics. We perform room temperature magneto-optical Kerr effect (MOKE) measurements at the band edge to directly probe the effect of Gd-doping (2.7×10¹⁹cm⁻³) on the valence and conduction band. While ferromagnetic GaMnAs shows huge Kerr signals (up to 5000 µrad)[2], no difference in Kerr rotation (within the 30 µrad sensitivity of our setup) is found in comparison with an undoped GaN reference sample. These findings are in agreement with recent XMCD data from Ney et. al. [3] and suggest that the ferromagnetism observed in SQUID measurements is not related to the GaN host matrix.
[1] S. Dhar et al., Phys. Rev. Lett. 94, 037205 (2005).
[2] A. V. Kimel et al., Phys. Rev. Lett. 94, 227203 (2005).
[3] A. Ney et al., Phys. Rev. B. 77, 233308 (2008).