Reverse Chemical Co-Precipitation: An Effective Method for Synthesis of BiFeO_3 Nanoparticles

The reverse chemical co-precipitation method was used for synthesis of the pure phase multiferroic bifeo_3 (bfo) nanoparticles. influence of different ph values on the microstructure and magnetic properties of the bfo nanopowders was investigated. the phase formation and the existence of impurity phases (like bi_25feo_39 and bi-2fe-4o_9) have been studied using x-ray diffractometry (xrd). the morphological features of the nanopowders were characterized using field emission scanning electron microscopy (fesem) and the presence of absorption bands at 400 to 3600 cm^-1 was investigated by fourier transformed infrared (ftir) spectroscopy. the magnetic evaluation of the synthesized powders was measured using vibrating sample magnetometery (vsm). the xrd results showed that the bfo powders have r3c crystal structure for all samples and also the diffraction patterns are perfectly indexed to the standard xrd card of bfo. the fesem micrographs showed irregular shape and average particle size of 71 to 95 and 182 nm for the as-synthesized powders with the ph values of 8.5, 9.5 and 10.5, respectively. the magnetic hysteresis loops indicated antiferromagnetic (weak ferromagnetic) behavior for all samples at room temperature. whereas the particles size of as-prepared powders were lower than the spiral spin cycloid (62 nm) and because of high surface-to-volume ratio of nanoparticles, which causes more uncompensated spins from the surface, the weak ferromagnetic behavior has been observed.