This article is cited in 2 papers

Lattice dynamics

Structural transformations in La$_{1-x}$Ba$_x$Mn$_{0.98}$ $^{57}$Fe$_{0.02}$O$_{3+\delta}$ ($x$ = 0.05–0.20)

V. D. Sedykh^a, V. S. Rusakov^b, I. I. Zver'kova^a, A. V. Dubovitskii^a, V. I. Kulakov<sup>a

a</sup> Osipyan Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow region
^b Lomonosov Moscow State University

Abstract: A systematic investigation of the structural transformations in La$_{1-x}$Ba$_x$Mn$_{0.98}$ $^{57}$Fe$_{0.02}$O$_{3+\delta}$ ($x$ = 0.05–0.20) at different Ba concentrations and under different heat treatment conditions (annealing in vacuum and in air) has been performed using the methods of Mössbauer spectroscopy and X-ray diffractometry. The samples have been synthesized by the sol-gel in air at a temperature of 1100$^\circ$C. For the studied range of barium concentrations, the synthesis results in the formation of a rhombohedral structure with space group $R\bar3c$. It has been shown that the annealing in vacuum leads to the transformation of the rhombohedral phase into a mixture of three phases, namely, PnmaI, PnmaII*, and PnmaII for all the barium concentrations under investigation. The content of the PnmaI phase increases with an increase in the barium concentration. However, even at a concentration of 20 at% Ba, the phases PnmaII and PnmaII* remain in small amounts in the sample.

Received: 27.07.2011

 English version: Physics of the Solid State, 2012, 54:3, 593–600

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