화학공학소재연구정보센터
Materials Chemistry and Physics, Vol.133, No.1, 103-109, 2012
Structural, transport and spectroscopic properties of Ti4+ substituted magnetite: Fe3-xTixO4
The effect of Ti4+ ion on the formation of magnetite, which were prepared by solid-state route reaction method, were studied by resistivity, Raman and Fe-57 Mossbauer spectrometry. Resistivity measured in the range of 10< T< 300 K for Ti4+ magnetite Fe3-xTixO4 exhibit first order phase transformations at the Verwey transition T-v for Fe3O4, Fe2.98Ti0.02O4 and Fe2.97Ti0.03O4 at 123 K and 118K, respectively. No first order phase transition was observed for Fe2.9Ti0.1O4 and small polaron model retraces the semiconducting resistivity behavior with activation energy of about 72 meV. The changes in Raman spectra as a function of doping show that the changes are gradual for samples with higher Ti doping. The Raman active mode for Fe2.9Ti0.1O4 at congruent to 634.4 cm(-1) is shifted as compared to parent Fe3O4 at congruent to 670 cm(-1), inferring that Mn2+ ions are located mostly on the octahedral sites. Fe-57 Mossbauer spectroscopy probes the site preference of the substitutions and their effect on the hyperfine magnetic fields confirms that TO ions are located mostly on the octahedral sites of the Fe3-xTixO4 spinel structure. (C) 2012 Elsevier B.V. All rights reserved.