Simultaneously enhanced piezoelectricity and curie temperature in BiFeO3-based high temperature piezoelectrics

We report the structure, dielectric, ferroelectric and piezoelectric properties of Cr-Mn co-doped (1- y )BiFe 1- x Cr x O 3 - y BaTi 1- x Mn x O 3 (0≤ x ≤0.04, 0.2≤ y ≤0.27) ceramics. By varying both x and y , a series of samples near morphotropic phase boundaries exhibiting both high ferroelectric Curie temperature T C (∼580−643 °C) and relatively large piezoelectric constant d 33 are constructed. Especially, the sample with y  = 0.24 and x  = 0.02 is found to show coexistence of high depolarization temperature T d (∼551 °C) and relatively large d 33 ∼116 pC/N, superior to most of those of BiFeO 3 based high-temperature piezoceramics reported previously. The enhanced ferroelectric T C in the Cr-Mn modified samples can be ascribed to the combined effects of large lattice distortion and high tetragonal phase content. These results demonstrate that constructing morphotropic phase boundaries via considering simultaneously the role of lattice distortion might be effective route to realize high-temperature and high piezoelectricity in BiFeO 3 -based systems.