Synthesis of BiFeO3 nanoparticles by the reverse chemical co-precipitation method: Influence of pH and study of the reaction mechanism

The reverse co-precipitation method was used for synthesis of the pure phase multiferroic BiFeO3 (BFO) nanoparticles. Influence of different pH value on the purity of bismuth ferrite powders was investigated. Thermogravimetric-differential thermal analysis (TG-DTA) technique indicated that the optimal temperature for calcination is 550°C. Atomic ratio of Bi to Fe is approximately 1:1 for BiFeO3 powders, as determined by energy dispersive spectroscopy (EDS). The phase formation and the existence of transient phases (like Bi25FeO39 and Bi2Fe4O9) has been studied using X-ray diffractometry (XRD). The morphological features of the nanopowders were characterized by field emission scanning electron microscopy (FESEM). The magnetic properties of the synthesized powders were measured using vibrating sample magnetometery (VSM). The results showed that the BFO powders have R3c crystal structure. The FESEM micrographs showed pseudo-cubic shape and particles size in the range of 25-234 nm. The magnetic hysteresis loops were indicated a weak ferromagnetic behavior of the samples at room temperature.