Effects of poling termination and aging process on piezoelectric properties of Mn-doped BaTi_0.96Zr_0.04O₃ ceramics

The effects of poling termination and aging process on the piezoelectric properties at room temperature of 1 mol% Mn-doped Ba(Ti_0.96Zr_0.04)O₃ ceramics with orthorhombic structure have been investigated. It is expected that the substitution of accepter Mn into the Ti_0.96Zr_0.04 site will result in a defect dipole with an oxygen vacancy and generate an internal field (Ed) in 1 mol% Mn-doped Ba(Ti_0.96Zr_0.04)O₃ ceramics. In order to investigate the effect of the rearrangement of defect dipoles on the piezoelectric properties, the following two investigations have been performed. One is on the relationship between the piezoelectric properties and the change in the poling-termination temperature (TP) around the orthorhombic- tetragonal temperature (TOT). The result shows that piezoelectric properties are related to spontaneous polarizations, and that the rearrangement of defect dipoles is small. The other is on the influence of aging treatment at 70 °C for 24 h on the piezoelectric properties. Above TOT, the piezoelectric properties are almost the same, independent of the TP of the specimen. This result suggests that the change in piezoelectric properties is due to a change in the domain in spontaneous polarizations and that the rearrangement of defect dipoles is also small. The result of domain observation reflection electron microscopy supports the rearrangement of spontaneous polarizations during the aging process.