This article is cited in 3 papers

Phase transitions

Mössbauer spectroscopy investigation of the La$_{1/3}$Sr$_{2/3}$FeO$_{3-\delta}$ perovskite

A. P. Chernyshev, S. A. Petrov, N. F. Uvarov

Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk

Abstract: The charge state of iron in the La$_{1/3}$Sr$_{2/3}$FeO$_{3-\delta}$ perovskite has been studied using Mössbauer spectroscopy. It has been found that, as the temperature decreases in the range of 200–162 K, the charge disproportionation occurs according to the scheme $^3$Fe$^{11/3+}$ $\to$ $^2$Fe$^{3.5+}$+Fe$^{4+}$ and the antiferromagnetic phase is formed. The charge disproportionation is due to condensation of hole bipolarons. Each of bipolarons is collectivized by a group of three ions. The collectivization occurs according to the scheme [3Fe$^{3+}$–2$\underline{L}$ ] $\to$ [2Fe$^{3+}$–$\underline{L}$ ] + [Fe$^{3+}$–$\underline{L}$ ]. Simultaneously, the energy gap is formed with the maximum width of 0.14 $\pm$ 0.02 eV determined by Mössbauer spectroscopy.

Received: 07.02.2014

 English version: Physics of the Solid State, 2014, 56:12, 2519–2523

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