Sin título
Idioma
en
Article de revue
Este ítem está publicado en
Solid State Sciences. 2010, vol. 12, n° 4, p. 476-481
Elsevier
Resumen en inglés
The La<sub>1</sub><sub>−</sub><i><sub>x</sub></i>Sr<i><sub>x</sub></i>Fe<sub>0.8</sub>Cr<sub>0.2</sub>O<sub>3</sub><sub>−</sub><i><sub>y</sub></i> (<i>x</i> = 0.2, 0.4, 0.6 and 0.8) phases were studied by X-ray photoelectron ...Leer más >
The La<sub>1</sub><sub>−</sub><i><sub>x</sub></i>Sr<i><sub>x</sub></i>Fe<sub>0.8</sub>Cr<sub>0.2</sub>O<sub>3</sub><sub>−</sub><i><sub>y</sub></i> (<i>x</i> = 0.2, 0.4, 0.6 and 0.8) phases were studied by X-ray photoelectron spectroscopy at room temperature and <sup>57</sup>Fe Mössbauer spectroscopy at different temperatures. Mixed valence states were observed both for chromium and iron ions, justifying the complex magnetic behaviour exhibited by these compounds. The Mössbauer results indicate the simultaneous presence of Fe<sup>3+</sup>, Fe<sup>4+</sup> and Fe<sup>5+</sup> at 4.2 K and the co-existence of Fe<sup>3+</sup> and Fe<sup>(3</sup><sup>+</sup><i><sup>n</sup></i><sup>)+</sup> at <i>T</i> = 293 K, with the latter fraction increasing with increasing strontium content. The presence of Cr<sup>3+/4+</sup> is interpreted as being mainly responsible for the incomplete charge disproportionation reaction of iron at low temperature, as deduced from the Mössbauer results.< Leer menos
Palabras clave en inglés
Mössbauer spectroscopy
X-ray photoelectron spectroscopy
Disproportionation reaction
Perovskite oxides
Orígen
Importado de HalCentros de investigación