High piezoelectric properties in 0.7BiFeO3–0.3BaTiO3 ceramics with MnO and MnO2 addition

BiFeO 3 –BaTiO 3 –based solid solutions are promising candidates for high–temperature piezoelectric devices because of their high Curie temperature ( T C ) and considerable electrical properties. Here, we reported an optimum composition of 0.7Bi(Fe 0.999 Mn 0.001 )O 3 –0.3BaTiO 3 ceramic with a large piezoelectric constant ( d 33 ) of 230 pC/N and a high T C of 505 °C, which was attributed to the intentional introducing of the ceramic with MnO and MnO 2 mixture. Furthermore, an in situ d 33 measurement was carried out, demonstrating excellent thermal stability for the 0.7Bi(Fe 0.999 Mn 0.001 )O 3 –0.3BaTiO 3 specimen. The d 33 remained above 200 pC/N in the temperature range of 25 °C–400 °C and its fluctuation was less than ± 15 %. It was determined that the high d 33 in the 0.7BiFe 0.999 Mn 0.001 )O 3 –0.3BaTiO 3 ceramic originated from a synergistic effect of rhombohedral distortion, intrinsic response, and ferroelectric order. The findings establish a solid correlation between electrical properties and phase/domain structure, and provide a novel approach to improve the piezoelectric properties for BiFeO 3 –BaTiO 3 –based ceramics.