Multiferroic properties of BiFeO3 ceramics prepared by spark plasma sintering with sol-gel powders under an oxidizing atmosphere

Multiferroic BiFeO3 ceramics are synthesized by spark plasma sintering along with sol-gel powders. During the sintering process, the pellets are surrounded by Al2O3 nanopowders to create an oxidizing atmosphere. The effects of Al2O3 nanopowders surrounding on the dielectric, ferroelectric and magnetic properties are investigated. Findings from X-ray diffraction and scanning electron microscopy demonstrate that the produced material is pure with an average grain size approximately from 1 to 3 mu m. Results from X-ray photoelectron spectroscopy indicate that the concentration of oxygen vacancies is lower for the samples prepared in the oxidizing atmosphere. Consequently, the prepared ceramics possess lower dielectric loss (0.01), reduced leakage current density (6.58 x 10(-8) A/cm(2)), larger remnant polarization (0.892 mu C/cm(2)) as well as good magnetic properties (maximum magnetization, M-m = 0.324 emu/g; remnant magnetization, M-r = 0.0024 emu/g).