V. D. Sedykh, V. S. Rusakov, I. I. Zver'kova, A. V. Dubovitskii, V. I. Kulakov, “Specific features of the structural transformations in La$_{1-x}$Ca$_x$Mn$_{0.98}$ $^{57}$Fe$_{0.02}$O$_{3+\delta}$ ($x$ = 0.05–0.50)”, Fizika Tverdogo Tela, 2011, Volume 53, Issue 7,Pages 1367

This article is cited in 9 papers

Lattice dynamics

Specific features of the structural transformations in La$_{1-x}$Ca$_x$Mn$_{0.98}$ $^{57}$Fe$_{0.02}$O$_{3+\delta}$ ($x$ = 0.05–0.50)

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

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

Abstract: The specific features of the structural transformations in La$_{1-x}$Ca$_x$Mn$_{0.98}$ $^{57}$Fe$_{0.02}$O$_{3+\delta}$ ($x$ = 0.05–0.50) at different Ca concentrations have been studied using Mössbauer spectroscopy and X-ray diffraction. Variations of the heat treatment conditions (annealing in vacuum and in air) cause reversible phase transitions. For calcium concentrations to 20%, a whole set of phases with reversible structural transitions, such as $Pnma$II $\leftrightarrow$ $Pmna$I $\leftrightarrow$ $R\bar3c$, can be obtained using the corresponding heat treatment. The phases are successively suppressed with increasing calcium concentration. The rhombohedral phase is suppressed for $x$ = 0.20. When the Ca concentration exceeds 20%, the PnmaII phase is suppressed; as a result, the PnmaI phase with equal concentrations of Mn$^{4+}$ and calcium stable during any heat treatments remains. The specific features of phase formation in the La$_{1-x}$Ca$_x$Mn$_{0.98}$ $^{57}$Fe$_{0.02}$O$_{3+\delta}$ compound doped with calcium and in the basis LaMnO$_{3+\delta}$ compound have been compared.

Received: 08.12.2010