Charge-Order Melting in Charge-Disproportionated Perovskite CeCu3Fe4O12

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• 作者：Ikuya Yamada ; Hidenobu Etani ; Makoto Murakami ; Naoaki Hayashi ; Takateru Kawakami ; Masaichiro Mizumaki ; Shigenori Ueda ; Hideki Abe ; Klaus-Dieter Liss ; Andrew J. Studer ; Tomoatsu Ozaki ; Shigeo Mori ; Ryoji Takahashi ; Tetsuo Irifune
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：November 3, 2014
• 年：2014
• 卷：53
• 期：21
• 页码：11794-11801
• 全文大小：532K
• ISSN：1520-510X

文摘

A novel quadruple perovskite oxide CeCu₃Fe₄O₁₂ has been synthesized under high-pressure and high-temperature conditions of 15 GPa and 1473 K. ⁵⁷Fe M枚ssbauer spectroscopy displays a charge disproportionation transition of 4Fe^3.5+ 鈫?3Fe³⁺ + Fe⁵⁺ below 鈭?70 K, whereas hard X-ray photoemission and soft X-ray absorption spectroscopy measurements confirm that the Ce and Cu valences are retained at approximately +4 and +2, respectively, over the entire temperature range measured. Electron and X-ray diffraction studies reveal that the body-centered cubic symmetry (space group Im3虆, No. 204) is retained at temperatures as low as 100 K, indicating the absence of any types of charge-ordering in the charge-disproportionated CeCu₃Fe₄O₁₂ phase. The magnetic susceptibility and neutron powder diffraction data illustrate that the antiferromagnetic ordering of Fe ions is predominant in the charge-disproportionated CeCu₃Fe₄O₁₂ phase. These findings suggest that CeCu₃Fe₄O₁₂ undergoes a new type of electronic phase in the ACu₃Fe₄O₁₂ series and that the melting of the charge-ordering in CeCu₃Fe₄O₁₂ is caused by the substantial decrease in the Fe valence and the resulting large deviation from the ideal abundance ratio of Fe³⁺:Fe⁵⁺ = 1:1 for rock-salt-type charge-ordering.