Interlayer Communication in Aurivillius Vanadate to Enable Defect Structures and Charge Ordering

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• 作者：Yaoqing Zhang ; Takafumi Yamamoto ; Mark A. Green ; Hiroshi Kageyama ; Yutaka Ueda
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：November 16, 2015
• 年：2015
• 卷：54
• 期：22
• 页码：10925-10933
• 全文大小：464K
• ISSN：1520-510X

文摘

The fluorite-like [Bi₂O₂]²⁺ layer is a fundamental building unit in a great variety of layered compounds. Here in this contribution, we presented a comprehensive study on an unusual Aurivillius phase Bi_3.6V₂O₁₀ with respect to its defect chemistry and polymorphism control as well as implications for fast oxide ion transport at lower temperatures. The bismuth oxide layer in Bi₄V₂O₁₁ is found to tolerate a large number of Bi vacancies without breaking the high temperature prototype I4/mmm structure (纬-phase). On cooling, an orthorhombic distortion occurs to the 纬-phase, giving rise to a different type of phase (B-phase) in the intermediate temperature region. Cooling to room temperature causes a further transition to an oxygen-vacancy ordered A-phase, which is accompanied by the charge ordering of V⁴⁺ and V⁵⁺ cations, providing magnetic (d¹) and nonmagnetic (d⁰) chains along the a axis. This is a novel charge ordering transition in terms of the concomitant change of oxygen coordination. Interestingly, upon quenching, both the 纬- and B-phase can be kinetically trapped, enabling the structural probing of the two phases at ambient temperature. Driven by the thermodynamic forces, the oxide anion in the 纬-phase undergoes an interlayer diffusion process to reshuffle the compositions of both Bi鈥揙 and V鈥揙 layers.