Introducing a Large Polar Tetragonal Distortion into Ba-Doped BiFeO3 by Low-Temperature Fluorination

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• 作者：Oliver Clemens ; Robert Kruk ; Eric A. Patterson ; Christoph Loho ; Christian Reitz ; Adrian J. Wright ; Kevin S. Knight ; Horst Hahn ; Peter R. Slater
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：December 1, 2014
• 年：2014
• 卷：53
• 期：23
• 页码：12572-12583
• 全文大小：569K
• ISSN：1520-510X

文摘

This article reports on the synthesis and crystallographic and magnetic structure of barium-doped BiFeO₃ compounds with approximate composition Bi_1鈥?i>xBa_xFeO_3鈥?i>x/2, as well as those of the fluorinated compounds Bi_1鈥?i>xBa_xFeO_3鈥?i>xF_x (both with x = 0.2, 0.3), prepared by low-temperature fluorination of the oxide precursors using polyvinylidenedifluoride. Whereas the oxide compounds were obtained as cubic (x = 0.2) and slightly tetragonal (x = 0.3, c/a 鈮?1.003) distorted perovskite compounds, a large tetragonal polar distortion was observed for the oxyfluoride compounds (c/a 鈮?1.08 for x = 0.2 and 鈭?.05 for x = 0.3), being isostructural to tetragonal PbTiO₃. Although described differently in previous reports on Ba-doped BiFeO₃, the observed remanent magnetization is found to agree well with the amount of BaFe₁₂O₁₉ only detectable by neutron diffraction and the well-known magnetic properties of BaFe₁₂O₁₉. The oxyfluoride compounds show G-type antiferromagnetic ordering with magnetic moments lying in the a/b plane.