Electrical properties of multiferroic BiFeO3 ceramics synthesized by spark plasma sintering

Single-phase multiferroic BiFeO3 powder was prepared by improved solid-state synthesis, and dense BiFeO3 ceramics were fabricated by a spark plasma sintering (SPS) process. The sintering temperature of SPS ranged from 650 to 800 °C under 50 MPa. It is found that the sample is not only single phased but also of high density when sintered at 650 °C. The dielectric constant and loss of the samples were tested between 100 Hz and 20 MHz at several temperatures. Oxygen and vacuum annealing conditions impact the dielectric behaviour of the BiFeO3 ceramics prepared by the SPS technique obviously. The piezoelectric coefficient d 33 of the sample annealed in vacuum is 4.2 pC N−1 at room temperature.