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

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• 作者：N. Ohon ; L. Vasylechko ; Yu. Prots ; M. Schmidt
• 关键词：A. Ceramics ; A. Oxides ; C. X-ray diffraction ; D. Crystal structure ; D. Phase equilibria
• 刊名：Materials Research Bulletin
• 出版年：February, 2014
• 年：2014
• 卷：50
• 期：Complete
• 页码：509-513
• 全文大小：954 K

文摘

Phase and structural behavior in the SmAlO₃-RAlO₃ (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 Sm_{1 鈭?#xA0;x}Eu_xAlO₃ and Sm_{1 鈭?#xA0;x}Gd_xAlO₃ 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 Sm_0.9Eu_0.1AlO₃ and Sm_0.9Gd_0.1AlO₃ samples have been found at 387 and 922 K and at 501 and 894 K. First-order reversible structural phase transformations 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.