Phase transition and thermal expansion property of Cr2-xZr0.5xMg0.5xMo3O12 solid solution

• Published in: 中国物理B：英文版 no. 6; pp. 433 - 439
• Main Author: 宋文博 王俊俏 李志远 刘献省 袁保合 梁二军
• Format: Journal Article
• Language: English
• Published: 01.06.2014
• Subjects: 单斜晶系; 固溶体; 斜方晶系; 斜方晶结构; 热膨胀性能; 相变; 相转变温度; 线性热膨胀系数
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/23/6/066501

Compounds with the formula Cr2-xZr0.5xMg0.5xMo3O12（x = 0.0, 0.3, 0.5, 0.9, 1.3, 1.5, 1.7, 1.9） are synthesized, and the effects of Zr4＋ and Mg2＋ co-incorporation on the phase transition, thermal expansion, and Raman mode are investigated. It is found that Cr2-xZr0.5xMg0.5xMo3O12 crystallize into monoclinic structures for x 〈 1.3 and orthorhombic structures for x _〉 1.5 at room temperature. The phase transition temperature from a monoclinic to an orthorhombic structure of Cr2Mo3O12 can be reduced by the partial substitution of （ZrMg）6＋ for Cr3＋. The overall linear thermal expansion coefficient decreases with the increase of the （ZrMg）6＋ content in an orthorhombic structure sample. The co-incorporation of Zr4＋ and Mg2＋ in the lattice results in the occurrence of new Raman modes and the hardening of the symmetric vibrational modes, which are attributed to the MoO4 tetrahedra sharing comers with ZrO6/MgO6 octahedra and to the strengthening of Mo-O bonds due to less electronegativities of Zr4＋ and Mg2＋ than Cr3＋, respectively.