Synthesis and properties of indium-doped hematite

Indium-doped hematite samples were prepared by calcination of indium-doped goethite samples and investigated using different instrumental techniques. In3+-for-Fe3+ substitution in the hematite structure was confirmed by the determination of the unit cell expansion using X-ray powder diffraction and by the measurement of the hyperfine magnetic field reduction using Mossbauer spectroscopy. Indium substitution in hematite also caused a decrease in the crystallite size, an increase in the particle size, a shift in the position of bands in infrared spectra, a decrease in the relative intensity of absorption bands in UV-Vis-NIR spectra and a disappearance of the Morin transition. Maximum substitution was estimated at about 8 mol%. (C) 2016 Elsevier B.V. All rights reserved.