Author/Authors :
Sangian, H Faculty of Materials and Metallurgical Engineering - Semnan University, Semnan, Iran , Mirzaee, O Faculty of Materials and Metallurgical Engineering - Semnan University, Semnan, Iran , Tajally, M Faculty of Materials and Metallurgical Engineering - Semnan University, Semnan, Iran
Abstract :
The reverse chemical co-precipitation method was used for synthesis of the pure phase multiferroic
BiFeO3 (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 Bi25FeO39 and Bi2Fe4O9) 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.
