Introducing a large polar tetragonal distortion into Ba-doped BiFeO3 by low-temperature fluorination

Inorg Chem. 2014 Dec 1;53(23):12572-83. doi: 10.1021/ic502183t. Epub 2014 Nov 10.

Abstract

This article reports on the synthesis and crystallographic and magnetic structure of barium-doped BiFeO3 compounds with approximate composition Bi(1-x)Ba(x)FeO(3-x/2), as well as those of the fluorinated compounds Bi(1-x)Ba(x)FeO(3-x)F(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 ≈ 1.003) distorted perovskite compounds, a large tetragonal polar distortion was observed for the oxyfluoride compounds (c/a ≈ 1.08 for x = 0.2 and ∼1.05 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Barium / chemistry*
  • Bismuth / chemistry*
  • Ferric Compounds / chemistry*
  • Halogenation*
  • Magnetic Phenomena
  • Molecular Structure
  • Temperature

Substances

  • Ferric Compounds
  • Barium
  • Bismuth