Structural Behaviour of Solid Solutions in the NdAlO3-SrTiO3 System

Natalia Ohon; Roman Stepchuk; Kostiantyn Blazhivskyi; Leonid Vasylechko

doi:10.1186/s11671-017-1937-8

Structural Behaviour of Solid Solutions in the NdAlO3-SrTiO3 System

Nanoscale Res Lett. 2017 Dec;12(1):148. doi: 10.1186/s11671-017-1937-8. Epub 2017 Feb 23.

Authors

Natalia Ohon¹, Roman Stepchuk¹, Kostiantyn Blazhivskyi¹, Leonid Vasylechko²

Affiliations

¹ Lviv Polytechnic National University, 12 Bandera Street, Lviv, 79013, Ukraine.
² Lviv Polytechnic National University, 12 Bandera Street, Lviv, 79013, Ukraine. crystal-lov@polynet.lviv.ua.

Abstract

Single-phase mixed aluminates-titanates Nd_1-x Sr _x Al_1-x Ti _x O₃ (x = 0.3 ÷ 0.9) were prepared from stoichiometric amounts of constituent oxides Nd₂O₃, Al₂O₃, TiO₂ and strontium carbonate SrCO₃ by solid-state reaction technique in air at 1773 K. Crystal structure parameters of Nd_1-x Sr _x Al_1-x Ti _x O₃ were refined by full-profile Rietveld refinement in space groups R [Formula: see text] c (x = 0.3, 0.5, 0.7 and 0.8) and Pm [Formula: see text] m (x = 0.9). Comparison of the obtained structural parameters with the literature data for the end members of the system NdAlO₃ and SrTiO₃ revealed formation of two kinds of solid solutions Nd_1-xSr_xAl_1-xTi_xO₃ with the cubic and rhombohedral perovskite structure. Morphotropic rhombohedral-to-cubic phase transition in Nd_1-xSr_xAl_1-xTi_xO₃ series occurs at x = 0.84. Based on the results obtained as well as the literature data for the parent compounds, the tentative phase diagram of the NdAlO₃-SrTiO₃ pseudo-binary system have been constructed.

Keywords: Crystal structure; Perovskite aluminates and titanates; Phase transition; Solid solution.