Suppression of Intersite Charge Transfer in Charge-Disproportionated Perovskite YCu3Fe4O12

详细信息    查看全文

• 作者：Hidenobu Etani ; Ikuya Yamada ; Kenya Ohgushi ; Naoaki Hayashi ; Yoshihiro Kusano ; Masaichiro Mizumaki ; Jungeun Kim ; Naruki Tsuji ; Ryoji Takahashi ; Norimasa Nishiyama ; Toru Inoue ; Tetsuo Irifune ; Mikio Takano
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：April 24, 2013
• 年：2013
• 卷：135
• 期：16
• 页码：6100-6106
• 全文大小：475K
• 年卷期：v.135,no.16(April 24, 2013)
• ISSN：1520-5126

文摘

A novel iron perovskite YCu₃Fe₄O₁₂ was synthesized under high pressure and high temperature of 15 GPa and 1273 K. Synchrotron X-ray and electron diffraction measurements have demonstrated that this compound crystallizes in the cubic AA鈥?sub>3B₄O₁₂-type perovskite structure (space group Im3̅, No. 204) with a lattice constant of a = 7.30764(10) 脜 at room temperature. YCu₃Fe₄O₁₂ exhibits a charge disproportionation of 8Fe^3.75+ 鈫?3Fe⁵⁺ + 5Fe³⁺, a ferrimagnetic ordering, and a metal-semiconductor-like transition simultaneously at 250 K, unlike the known isoelectronic compound LaCu₃Fe₄O₁₂ that currently shows an intersite charge transfer of 3Cu²⁺ + 4Fe^3.75+ 鈫?3Cu³⁺ + 4Fe³⁺, an antiferromagnetic ordering, and a metal鈥搃nsulator transition at 393 K. This finding suggests that intersite charge transfer is not the only way of relieving the instability of the Fe^3.75+ state in the A³⁺Cu²⁺₃Fe^3.75+₄O₁₂ perovskites. Crystal structure analysis reveals that bond strain, rather than the charge account of the A-site alone, which is enhanced by large A³⁺ ions, play an important role in determining which of intersite charge transfer or charge disproportionation is practical.