Unraveling optimized parameters for phase pure rhombohedral perovskite bismuth ferrite without leaching.

Bismuth ferrite (BiFeO3 or BFO in short), one of the very promising multi-ferroic materials possessing a rhombohedrally distorted perovskite structure, has been synthesized using conventional solid-state reaction method. Eight sets of samples were prepared by varying initial synthesis parameters. Effects of precursors' grinding time, heating rate, quenching rate and sintering temperature on the phase, structural and spectral properties of obtained materials were systematically studied using XRD, FTIR and Rietveld methods. The results revealed that the optimal condition to obtain pure-phase BiFeO3 is using preheated furnace with sintering at 1073 K and then quenching in air for rapid cooling with intermediate grinding time of 3 h. Rietveld analysis applied on the X-ray diffraction data via Fullprof software indicated around 97% purity of the sample with the above-mentioned conditions. Deviation from the above temperature or grinding time or quenching rate leads to an increase in the phase fractions of Bi2Fe4O9 and Bi25FeO40 which are the major secondary phases formed during the synthesis of bismuth ferrite. [ABSTRACT FROM AUTHOR]