Synthesis, structural and magnetic characterisation of the fully fluorinated compound 6H-BaFeO₂F

The compound 6H-BaFeO2F (P63/mmc) was synthesised by the low temperature fluorination of 6H-BaFeO3–d using polyvinylidenedifluoride (PVDF) as a fluorination agent. Structural characterisation by XRD and NPD suggests that the local positions of the oxygen and fluorine atoms vary with no evidence for ordering on the anion sites. This compound shows antiferromagnetic ordering at room temperature with antiparallel alignment of the magnetic moments along the c-axis. The use of PVDF also allows the possibility of tuning the fluorine content in materials of composition 6H-BaFeO3–dFy to any value of 0<y≤1. In addition, the oxygen content, and therefore the iron oxidation state, can be tuned by applying different partial pressures of oxygen during the reaction.