High-Pressure Synthesis, Crystal Structure, and Electromagnetic Properties of CdRh2O4: an Analogous Oxide of the Postspinel Mineral MgAl2O4

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• 作者：Xia Wang ; Yanfeng Guo ; Youguo Shi ; Alexei A. Belik ; Yoshihiro Tsujimoto ; Wei Yi ; Ying Sun ; Yuichi Shirako ; Masao Arai ; Masaki Akaogi ; Yoshitaka Matsushita ; Kazunari Yamaura
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：June 18, 2012
• 年：2012
• 卷：51
• 期：12
• 页码：6868-6875
• 全文大小：379K
• 年卷期：v.51,no.12(June 18, 2012)
• ISSN：1520-510X

文摘

The postspinel mineral MgAl₂O₄ exists only under the severe pressure conditions in the subducted oceanic lithosphere in the Earth鈥檚 deep interior. Here we report that its analogous oxide CdRh₂O₄ exhibits a structural transition to a quenchable postspinel phase under a high pressure of 6 GPa at 1400 掳C, which is within the general pressure range of a conventional single-stage multianvil system. In addition, the complex magnetic contributions to the lattice and metal nonstoichiometry that often complicate investigations of other analogues of MgAl₂O₄ are absent in CdRh₂O₄. X-ray crystallography revealed that this postspinel phase has an orthorhombic CaFe₂O₄ structure, thus making it a practical analogue for investigations into the geophysical role of postspinel MgAl₂O₄. Replacement of Mg²⁺ with Cd²⁺ appears to be effective in lowering the pressure required for transition, as was suggested for CdGeO₃. In addition, Rh³⁺ could also contribute to this reduction, as many analogous Rh oxides of aluminous and silicic minerals have been quenched from lower-pressure conditions.