Concentration and temperature-driven phase transitions in the NdAlO ₃-EuAlO₃ system

Phase and structural behaviour in the NdAlO3-EuAlO3 system has been studied in a whole concentration range. Depending on x two kinds of solid solutions Nd1-xEuxAlO3 one with rhombohedral (x ≤ 0.15) and one with orthorhombic (x ≥ 0.25) symmetry exist at room temperature. A morphotropic phase transition occurs at x ≈ 0.20, where the co-existence of both phases was observed. First-order structural phase transition Pbnm↔R 3 c has been detected in Nd0.6Eu 0.4AlO3 at 627 K both from in situ high-temperature X-ray synchrotron powder diffraction and thermal analysis data. © 2012 IEEE

Phase and structural behavior of SmAlO₃–RAlO₃ (R = Eu, Gd) systems

Phase and structural behavior in the SmAlO3–R AlO3 (R = Eu, Gd) systems has been studied in a whole concentration range by means of laboratory X-ray diffraction, in situ synchrotron powder diffraction and differential thermal analysis techniques. Continuous solid solutions with orthorhombic perovskite structure have been found in both systems. Peculiarity of the solid solutions of Sm1 − xEuxAlO3 and Sm1 − xGdxAlO3 is the existence of two lattice parameter crossovers in each system occurred at x Eu = 0.07 and 0.62 and at x Gd = 0.04 and 0.33, respectively. The temperature induced lattice crossovers in the Sm0.9Eu0.1AlO3 and Sm0.9Gd0.1AlO3 samples have been found at 387 and 922 K and at 501 and 894 K. First-order reversible structural phase transformations View the MathML sourcePbnm↔R3¯c have been detected in both systems at the elevated temperatures. The temperatures of these transitions increase linearly with the decreasing of the samarium content. Phase diagrams of the pseudo-binary systems SmAlO3–EuAlO3 and SmAlO3–GdAlO3 have been constructed

Concentration- and temperature-induced phase transitions in NdAlO₃-TbAlO₃ and NdAlO₃-DyAlO₃ systems

Phase and structural behaviour in the NdAlO3-RAlO3 ( R = Tb, Dy) systems has been studied in a wide concentration and temperature ranges. Two kinds of solid solutions Nd1-xTbxAlO3 and Nd1-xDyxAlO3 with rhombohedral (space group No 167 R (3) over tilde c) and orthorhombic (space group No 62 Pbnm) perovskite structure are formed in these systems. Morphotropic phase transition between two perovskite-like structures occurs at x = 0.1 for Nd1-xTbxAlO3 and at x = 0.05-0.1 for Nd1-xDyxAlO3. First-order structural phase transition Pbnm R (3) over bar c has been detected in Nd0.8Tb0.2AlO3, N0.6Tb0.4AlO3, Nd0.8Dy0.2AlO3 and Nd0.7Dy0.3AlO3 samples at 540 K, 1174 K, 687 K and 900 K, respectively. Phase diagrams of the pseudo-binary systems NdAlO3-TbAlO3 and NdAlO3-DyAlO3 have been constructed. (C) 2016 Elsevier B.V. All rights reserved