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

BiFeO3–BaTiO3–based solid solutions are promising candidates for high–temperature piezoelectric devices because of their high Curie temperature (TC) and considerable electrical properties. Here, we reported an optimum composition of 0.7Bi(Fe0.999Mn0.001)O3–0.3BaTiO3 ceramic with a large piezoelectric constant (d33) of 230 pC/N and a high TC of 505 °C, which was attributed to the intentional introducing of the ceramic with MnO and MnO2 mixture. Furthermore, an in situ d33 measurement was carried out, demonstrating excellent thermal stability for the 0.7Bi(Fe0.999Mn0.001)O3–0.3BaTiO3 specimen. The d33 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 d33 in the 0.7BiFe0.999Mn0.001)O3–0.3BaTiO3 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 BiFeO3–BaTiO3–based ceramics.