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

作者：Song Wen Bo; Wang Jun Qiao; Li Zhi Yuan; Liu Xian Sheng; Yuan Bao He; Liang Er Jun^*

来源：Chinese Physics B, 2014, 23(6): 066501.

DOI：10.1088/1674-1056/23/6/066501

• negative thermal expansion material
• phase transition
• Raman spectroscopy

Compounds with the formula Cr2-0xZr0.5xMg0.5xMo3O12 (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 Cr2-0xZr0.5xMg0.5xMo3O12 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 corners with ZrO6/MgO6 octahedra and to the strengthening of Mo-O bonds due to less electronegativities of Zr4+ and Mg2+ than Cr3+, respectively.

• 出版日期2014-6
• 单位郑州大学