BiFeO3 powders were prepared by a sol-gel process at different calcination temperatures. The DTA curve shows an obvious exothermic peak near 480.5 οC, a temperature close to the BiFeO3 formation temperature, which is in agreement with the XRD result (450 οC). Having been calcined at 600 οC for 1 h, XRD spectra has the emergence of several sharp diffraction peaks in correspondence with the standard XRD spectrum of the crystalline BiFeO3. As the calcination temperature was increased, the diffraction peak intensity of the XRD spectra of BiFeO3 gradually was enhanced and the diffraction peaks became sharper. There is a clear endothermic peak near 825.1 οC, which is the transition temperature from the α phase to β phase and in good agreement with the reported Curie temperature. The average size of powders determined by XRD and TEM gradually increases with an increase in the calcination temperature. A shell-core structure is distinctly observed in powders calcined at 400 οC

Keywords: Bismuth ferrite, Nanopowder, Multiferroic, Sol-gel.