Oxygen Nonstoichiometry and Valence State of Manganese in La<sub>1–<i>x</i></sub>Ca<sub><i>x</i></sub>MnO<sub>3+δ</sub>
Sabrina A. Heuer, Roland Schierholz, Evgeny V. Alekseev, L. Peters, David N. Mueller, Tomáš Duchoň, Vaibhav Vibhu, Hermann Tempel, L.G.J. de Haart, Hans Kungl, Rüdiger‐A. Eichel
Abstract
= 0-0.5) was synthesized using conventional solid-state synthesis under an air atmosphere. The structures of the materials were studied in detail with powder X-ray diffraction. The initial oxygen nonstoichiometries were determined using thermogravimetric reduction. The samples were subsequently analyzed in terms of defect chemistry in dependence of temperature, atmosphere, and Ca content via thermogravimetric analysis. The changes in the manganese charge states were investigated by X-ray absorption near-edge spectroscopy experiments. The influence of intrinsic and extrinsic effects on the Mn-valence state of the differently Ca-substituted samples as calculated from thermogravimetric analysis and as determined directly from X-ray absorption near-edge spectroscopy is presented.