Lattice sites, charge states and spin–lattice relaxation of Fe ions in 57Mn+ implanted GaN and AlN

Autor: Deena Naidoo, Hilary Masenda, H. P. Gislason, Guido Langouche, Haraldur P. Gunnlaugsson, Krish Bharuth-Ram, Sveinn Olafsson, G. Weyer, Karl Johnston, S. Shayestehaminzadeh, Roberto Mantovan, T. E. Mølholt, M. Ncube
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Journal of Magnetism and Magnetic Materials
Masenda, H, Naidoo, D, Bharuth-Ram, K, Gunnlaugsson, H P, Johnston, K, Mantovan, R, Molholt, T E, Ncube, M, Shayestehaminzadeh, S, Gislason, H P, Langouche, G, Ólafsson, S & Weyer, G 2016, ' Lattice sites, charge states and spin-lattice relaxation of Fe ions in Mn-57(+) implanted GaN and AIN ', Journal of Magnetism and Magnetic Materials, vol. 401, pp. 1130-1138 . https://doi.org/10.1016/j.jmmm.2015.11.026
Popis: The lattice sites, valence states, resulting magnetic behaviour and spin-lattice relaxation of Fe ions in GaN and AIN were investigated by emission Mossbauer spectroscopy following the implantation of radioactive Mn-57(+) ions at ISOLDE/CERN. Angle dependent measurements performed at room temperature on the 14.4 keV gamma-rays from the Fe-57 Mossbauer state (populated from the Mn-57/beta(-) decay) reveal that the majority of the Fe ions are in the 2+ valence state nearly substituting the Ga and Al cations, and/or associated with vacancy type defects. Emission Mossbauer spectroscopy experiments conducted over a temperature range of 100-800 K show the presence of magnetically split sextets in the "wings" of the spectra for both materials. The temperature dependence of the sextets relates these spectral features to paramagnetic Fe3+ with rather slow spin-lattice relaxation rates which follow a T-2 temperature dependence characteristic of a two-phonon Raman process. (C) 2015 Elsevier B.V. All rights reserved.
Databáze: OpenAIRE