Investigation of the annealing temperature effect on structural, morphology, dielectric and magnetic properties of BiFeO3 nanoparticles

Highlights: • The BiFeO₃ nanoparticles were synthesized using the sol-gel method and annealed at different temperatures. • The BiFeO₃ phase purity increases at higher annealing temperature. • The samples with small particle sizes show ferromagnetic phase at room temperature. • Decrease in dielectric constant was observed by increasing annealing temperature. - Abstract: In this paper we have investigated the annealing temperature effect on the structure, morphology, dielectric and magnetic properties of sol-gel synthesized multiferroic BiFeO₃ nanoparticles. X-ray diffraction spectroscopy revealed that all the samples have rhombohedrally distorted perovskite structure and the most pure BFO phase is obtained on the sample annealed at 800 °C. Field emission scanning electron microscopy (FESEM) revealed that increasing annealing temperature would increase the particle size. Decrease in dielectric constant was also observed by increasing annealing temperature. Vibrating sample method (VSM) analysis confirmed that samples annealed at 500–700 °C with particle size below the BFO's spiral spin structure length, have well saturated M–H curve and show ferromagnetic behavior.