2019 Volume 127 Issue 6 Pages 383-387
The effects of oxygen partial pressure (pO2) during sintering and post-annealing treatment on the microstructure and electrical properties of Mn-added 0.3BaTiO3–0.1Bi(Mg1/2Ti1/2)O3–0.6BiFeO3 ceramics were investigated. The ceramics sintered at pO2 of 0.1–1 atm showed pinched polarization–electric field (P–E) loops, while the ceramics sintered in nitrogen gas could not be measured due to dielectric breakdown. By annealed at 800°C for 5 h and cooled slowly, the ceramics showed increased remanent polarizations although their P–E loops were still pinched. When the as-sintered ceramics were annealed at 800°C for 5 h and then quenched into water, well-developed ferroelectric hysteresis loops were observed. These results were discussed with grain size and defect dipoles consisted of oxygen vacancies and bismuth vacancies or iron ions with a different valence.