Effect of fabrication routes on the microstructure, the dielectric and ferroelectric properties of the Mn-doped BaTiO3 ceramics

The effect of fabrication routes on the microstructure, the dielectric and ferroelectric properties of the Mn-doped BaTiO3 ceramics was systematically studied in the present study. It can be concluded that the ways of doping manganese into BaTiO3 matrix had a strong impact on the obtained ceramics. Doping manganese after the calcination of BaTiO3 (BT + Mn) would inhibit the grain growth and cause the hexagonal BaTiO3 when sintered at 1,400 °C in the air. While doping manganese at the initial stage [BaTi(1−x)MnxO3], no hexagonal BaTiO3 is detected in the same sintering temperature. As the macroscopic properties, the dielectric properties showed permittivity diffusion with the frequency in the temperature range of −10 to 150 °C only in the ceramics fabricated by the former route (BT + Mn). Moreover, the dielectric relaxation process disappeared after aging treatment only in the ceramics fabricated by the later route [BaTi(1−x)MnxO3]. The ferroelectric properties showed strong aging effect in the sample fabricated by the latter route [BaTi(1−x)MnxO3] both with fine grain and coarse grain, while the sample fabricated by the former route (BT + Mn) showed slight aging phenomenon ever after aging at room temperature for 10 days. The electrostrain also showed big difference within different samples: The recoverable electrostrain were 0.11 % (BT + Mn) and 0.21 % [BaTi(1−x)MnxO3] at the same sintering temperature of 1,320 °C and aging in the room temperature for 10 days. Such results were analyzed from the viewpoint of the differences in solubility of manganese and the consequent manganese–oxygen vacancy defect dipoles in the different fabrication routes.