States of dilute Fe in SnO2 have been monitored using 57Fe emission Mössbauer spectroscopy following implantation of 57Mn (T 1/2 = 85.4 s) in the temperature range from 143 K to 711 K. A sharp annealing stage is observed at ~330 K where the Fe3 + /Fe2 + ratio shows a marked increase. It is suggested that this annealing stage is due to the dissociation of Mn-VO pairs during the lifetime of 57Mn; the activation energy for this dissociation is estimated to be 0.9(1) eV. Fe3 + is found in a paramagnetic state showing spin-lattice relaxation rates consistent with an expected T 2 dependence derived for a Raman process. In addition, a sharp lined doublet in the Mössbauer spectra is interpreted as due to recoil produced interstitial Fe.
Springer International Publishing
1 Apr 2014
Volume: 226 Issue: 1-3 Pages: 389-396