Long Youwen, Saito Takashi, Tohyama Takenori, Oka Kengo, Azuma Masaki, Shimakawa Yuichi
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Inorg Chem. 2009 Sep 7;48(17):8489-92. doi: 10.1021/ic901128k.
An A-site-ordered double perovskite BiCu(3)Fe(4)O(12) was synthesized at high-pressure and high-temperature conditions. Similar to the isostructural LaCu(3)Fe(4)O(12), the temperature-induced intermetallic charge transfer between the A'-site Cu and the B-site Fe ions occurs but at higher temperature (428 K) than LaCu(3)Fe(4)O(12) (393 K) does. This charge transfer causes an isostructural phase transition with volume contraction by 0.6% as well as semiconductor-to-metal and antiferromagnetism-to-paramagnetism transitions. Although the Bi cation at the A site does not take part in the charge transfer, it appears to enhance the charge-transfer temperature by stabilizing the square-planar coordinated Cu(3+).
一种A位有序的双钙钛矿BiCu₃Fe₄O₁₂在高压和高温条件下合成。与同结构的LaCu₃Fe₄O₁₂相似，在A'位Cu和B位Fe离子之间发生了温度诱导的金属间电荷转移，但发生温度（428 K）高于LaCu₃Fe₄O₁₂（393 K）。这种电荷转移导致了同结构的相变，体积收缩0.6%，同时发生半导体到金属以及反铁磁性到顺磁性的转变。尽管A位的Bi阳离子不参与电荷转移，但它似乎通过稳定平面正方形配位的Cu³⁺提高了电荷转移温度。
