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Intermetallic charge transfer in A-site-ordered double perovskite BiCu3Fe4O12
Youwen Long1, Takashi Saito, Takenori Tohyama
1Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan. ywlong@msk.kuicr.kyoto-u.ac.jp
Abstract:
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+).
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