Synthesis of Bi2Fe4O9 via PVA sol–gel route

Bi2Fe4O9 powders were synthesized by a sol–gel process using polyvinyl alcohol (PVA) as a complexing agent. Differential scanning calorimetry (DSC), thermogravimetric (TG), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Field emission scanning electron microscope (FSEM) 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 Bi2Fe4O9 was investigated. XRD analysis showed that single-phase Bi2Fe4O9 was obtained from the Mn+/–OH = 2:1 and Mn+/–OH = 1:1 precursors at the temperature of 700 °C. For the precursor with Mn+/–OH = 4:1, pure Bi2Fe4O9 formed at the temperature of 800 °C. Bi2Fe4O9 powders clacined at 700 °C from Mn+/–OH = 2:1 precursor shows weak ferromagnetism.