Insight into the Effects of Fe Addition on the Local Structure and Electronic Properties of SrTiO3
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Data
2014-03-06
Autores
Silva, Luis F. da
M'Peko, Jean-Claude
Andres, Juan
Beltran, Armando
Gracia, Lourdes
Bernardi, Maria I. B.
Mesquita, Alexandre [UNESP]
Antonelli, Eduardo
Moreira, Mario L.
Mastelaro, Valmor R.
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Amer Chemical Soc
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This paper reports an experimental and theoretical investigation of the effects of adding Fe to the perovskite strontium titanate SrTiO3. The effects include changes in the short-order range structure as well as in the electronic and electrical properties. X-ray diffraction analysis reveals that the SrTi1-xFexO3 network shrinks with increasing Fe content, while X-ray absorption spectroscopy measurements of the Ti and Fe K-edge revealed the presence of some under-coordinated TiO5 units created because of the partial replacement of Fe3+ ions in the Ti4+. site. UV-visible absorption spectra indicated a reduction in optical gap with increasing Fe content. The electronic structure and spin densities of STFO with x = 0, 0.0625, 0.125, 0.5, and 1 are calculated by the OFT method at the B3LYP computational level, showing a Jahn-Teller distortion of O atoms surrounding the Fe as well as the formation of under-coordinated TiO5 units. From the electrical viewpoint, the results show that STFO is a mixed (ionic and electronic) conductor and that the electronic contribution becomes dominant with increasing Fe content.
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Journal Of Physical Chemistry C. Washington: Amer Chemical Soc, v. 118, n. 9, p. 4930-4940, 2014.