4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
The Proceedings of SAIP2016 published on 24 December 2017
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Search for dilute magnetism in 3d doped III-Nitrides - Results from Mössbauer Spectroscopy

Presented by Dr. Hilary MASENDA on 8 Jul 2016 from 15:20 to 15:40
Type: Oral Presentation
Track: Track A - Division for Physics of Condensed Matter and Materials


ZnO and GaN doped with transitions metals have attracted much attention since the theoretical prediction<sup>[1]</sup> that wide band-gap materials are potential dilute magnetic semiconductors with high Curie temperatures (<i>T</i><sub>c</sub> ≥ 300 K), resulting from carrier mediated magnetic interactions due to itinerant holes coupling with localized dopant spins. This motivated our investigations on the site occupancy and magnetic behaviour of Fe ions in III-nitrides using emission Mössbauer spectroscopy (eMS) following the implantation of radioactive Mn<sup>+</sup> ions at ISOLDE/CERN. Angle dependent measurements performed at room temperature on the 14.4 keV &gamma;-rays from the <sup>57</sup>Fe Mössbauer state (populated from the <sup>57</sup>Mn &beta;<sup>-</sup> decay) reveal that the majority of the Fe ions are in the 2+ valence state located near substitutional and/or associated with vacancy type defects. eMS experiments conducted over a temperature range of 100-800 K show the presence of magnetically-split sextets in the “wings” of the spectra for GaN and AlN, as observed in ZnO<sup>[2]</sup>. The temperature dependence of the sextets relate these spectral features to paramagnetic Fe<sup>3+</sup> (S=5/2) with rather slow spin-lattice relaxation rates which follow a <i>T</i><sup>2</sup> temperature dependence characteristic of a two-phonon Raman process. However, InN did not show the presence of any magnetic structure in the spectra suggesting the absence of high spin Fe<sup>3+</sup> in the material. These results will be compared to those obtained in 3<i>d</i>-doped ZnO<sup>[3]</sup>. <p>[1] Dietl, T. et al: Science, 287 (2000) 1019.</p> <p>[2] Gunnlaugsson, H. P., et al: Appl. Phys. Lett., 97 (2010) 142501.</p> <p>[3] Mølholt, T. E. et al: Phys. Scr., T148 (2012) 014006.</p>










Location: Kramer Law building
Address: UCT Middle Campus Cape Town
Room: LT1

Primary authors

  • Dr. Hilary MASENDA School of Physics, University of the Witwatersrand, Johannesburg, 2050, South Africa


  • Prof. Deena NAIDOO School of Physics, University of the Witwatersrand, Johannesburg, 2050, South Africa
  • Prof. Guido LANGOUCHE Instituut voor Kern- en Stralings fysika, University of Leuven (KU Leuven), Belgium
  • Prof. Hafliði Pétur GíSLASON Science Institute, University of Iceland, Dunhaga 3,107 Reykjavík, Iceland,
  • Prof. Gerd WEYER Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus, Denmark