Low-Temperature Synthesis of BiFeO3 via PVA Sol-Gel Route

Bismuth ferrite (BiFeO3) powders were synthesized by a sol-gel process using polyvinyl alcohol (PVA) as a complexing agent. Thermogravimetric, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and field-emission scanning electron microscope techniques were used to characterize precursor and derived oxide powders. The effect of the ratios of positively charged valences to hydroxyl groups of PVA (Mn+/-OH) on the formation of BiFeO3 was investigated. XRD analysis showed that single-phase and well-crystallized BiFeO3 was obtained from the Mn+/-OH = 2:1 precursor at a temperature as low as 400 degrees C. For the precursor with Mn+/-OH = 4:1, BiFeO3 formed only at the temperature of 600 degrees C. With Mn+/-OH = 1:1 and 1.5:1 precursor, pure BiFeO3 powder was not obtained. In present work, single-phase BiFeO3 can be formed at lower temperature and less organics are required; furthermore, the process is simple and easy to control.