Charge-order melting in charge-disproportionated perovskite CeCu3Fe4O12

A novel quadruple perovskite oxide CeCu3Fe4O12 has been synthesized under high-pressure and high-temperature conditions of 15 GPa and 1473 K. (57)Fe Mössbauer spectroscopy displays a charge disproportionation transition of 4Fe(3.5+) → 3Fe(3+) + Fe(5+) below ∼270 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 Im3̅, 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 Fe(3+):Fe(5+) = 1:1 for rock-salt-type charge-ordering. © 2014, American Chemical Society.

Keywords

Perovskite, Spectroscopy, Temperature range, X-ray sources, Photoemission, Antiferromagnetic materials

Citation

Yamada, I., Etani, H., Murakami, M., Hayashi, N., Kawakami, T., Mizumaki, M.,Ueda, S., Abe, H., Liss, K. D., Studer, A. J., Ozaki, T., Mori, S., Takahashi, R., & Irifune, T. (2014). Charge-order melting in charge-disproportionated perovskite CeCu3Fe4O12. Inorganic Chemistry, 53(21), 11794-11801. doi:10.1021/ic502138v