data_Bi0.8Ba0.2FeO2.8F0.2 _audit_update_record ; 2014-10-20 # Formatted by publCIF ; #coupled refinement of neutron and X-ray data, only data for x-rays given _diffrn_ambient_temperature 298 _diffrn_radiation_wavelength 1.54176 _diffrn_radiation_type 'Cu K\a' _cell_measurement_theta_min 2.5 _cell_measurement_theta_max 65 _symmetry_cell_setting tetragonal #Added by publCIF _cell_formula_units_Z 1 #Added by publCIF _cell_measurement_temperature 298 #Added by publCIF _chemical_formula_weight 299.09 #Added by publCIF _chemical_formula_iupac 'Ba0.2 Bi0.8 Fe1 O2.8 F0.2' _chemical_formula_sum 'Ba0.2 Bi0.8 F0.2 Fe1 O2.8' #Added by publCIF _publ_section_abstract ; This article reports on the synthesis, crystallographic and magnetic structure of Babarium doped BiFeO3 compounds with approximate composition Bi1 xBaxFeO3 x/2, as well as of the fluorinated compounds Bi1 xBaxFeO3-xFx (both with x = 0.2, 0.3), prepared by low temperature fluorination of the oxide precursors using polyvinylidenedifluoride, PVDF. Whereas the oxide compounds were obtained as cubic (x = 0.2) resp. slightly tetragonal (x = 0.3, c/a ca. 1.003) distorted perovskite compounds, a large tetragonal polar distortion was observed for the oxyfluoride compounds (c/a ca. 1.08 for x = 0.2 and ca. 1.05 for x = 0.3), being isostructural to tetragonal PbTiO3. Although described differently in previous reports on Ba doped BiFeO3, the observed remanent magnetisation 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. ; _publ_section_keywords ; BiFeO3; fluorination; tetragonal distortion; magnetic properties; magnetic structure ; _publ_section_title ; Introducing a large polar tetragonal distortion into Ba-doped BiFeO3 by low temperature fluorination ; _chemical_name_mineral 'bismuth barium iron oxide fluoride' _cell_length_a 3.9118(2) _cell_length_b 3.9118(2) _cell_length_c 4.2589(7) _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 65.170(13) _symmetry_space_group_name_H-M P4mm loop_ _symmetry_equiv_pos_as_xyz 'x, y, z ' '-x, y, z ' '-y, -x, z ' '-y, x, z ' 'y, -x, z ' 'y, x, z ' 'x, -y, z ' '-x, -y, z ' loop_ _atom_site_label _atom_site_type_symbol _atom_site_symmetry_multiplicity _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Bi Bi+3 1 0 0 -0.093(1) 0.8 Ba Ba+2 1 0 0 0.010(8) 0.2 Fe Fe+3 1 0.5 0.5 0.5 1 O1 O-2 1 0.5 0.5 0.043(1) 0.933 F1 F-1 1 0.5 0.5 0.043(1) 0.067 O2 O-2 2 0 0.5 0.570(1) 0.933 F2 F-1 2 0 0.5 0.570(1) 0.067 loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 Bi 0.043(1) 0.043(1) 0.037(3) 0 0 0 Ba 0.043(1) 0.043(1) 0.037(3) 0 0 0 Fe 0.006(1) 0.006(1) 0.016(1) 0 0 0 O1 0.057(1) 0.057(1) 0.003(2) 0 0 0 F1 0.057(1) 0.057(1) 0.003(2) 0 0 0 O2 0.026(1) 0.026(1) 0.024(2) 0 0 0 F2 0.026(1) 0.026(1) 0.024(2) 0 0 0