Untitled
Language
en
Article de revue
This item was published in
Solid State Sciences. 2010, vol. 12, n° 4, p. 476-481
Elsevier
English Abstract
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 ...Read more >
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.Read less <
English Keywords
Mössbauer spectroscopy
X-ray photoelectron spectroscopy
Disproportionation reaction
Perovskite oxides
Origin
Hal imported