Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 89: Transport II
HL 89.4: Talk
Thursday, March 14, 2013, 17:30–17:45, H16
Electron spin dynamics in Gd-implanted GaN — •Jörg Rudolph1, Jan Heye Buß1, Stepan Shvarkov2, Andreas D. Wieck2, and Daniel Hägele1 — 1AG Spektroskopie der kondensierten Materie, Ruhr-Universität Bochum, Bochum, Germany — 2Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
Dilute magnetic semiconductors (DMS) are a
prerequisite for the development and realization of a spin-based
electronics. GaN-based DMS have attracted strong interest in the
last years, with a special focus on Gd-doped GaN after reports of
ferromagnetism with Curie temperatures far above room-temperature
[1]. Experimental evidence for high-temperature ferromagnetism
in Gd:GaN was, however, always based on integral measurements of
the magnetization by SQUIDs, while complementary methods like
x-ray magnetic dichroism or magnetic resonance techniques could
not corroborate the claimed ferromagnetism [2]. We measure the
electron spin dynamics in GaN implanted with different Gd
densities as well as coimplanted with Si by time-resolved
magneto-optical Kerr-rotation spectroscopy. We find strongly
increased electron spinlifetimes for an intermediate Gd
concentration. This strong increase is, however, shown to be a
consequence of the high defect density created during the ion
implantation, and not a consequence
of a magnetic effect of the Gd ions.
[1] S. Dhar et al., Phys. Rev. Lett. 94,
037205 (2005)
[2] A. Ney et al., J. Magn. Magn. Mat. 322,
1162 (2010)