Electromechanical properties of acceptor-doped lead-free piezoelectrics

In this paper, the processing and electrocmechanical of Mn-doped BNT-based ceramics prepared by mixed oxide route have been studied. Different amounts of Mn (0.01, 0.014, 0.015, 0.016, 0.017, 0.02, and 0.022) were doped to the 0.88[Bi
_0.5
Na
_0.5
TiO
₃
]-0.08[Bi
_0.5
K
_0.5
TiO
₃
]-0.04[Bi
_0.5
Li
_0.5
TiO
₃
] ceramics. Samples were sintered at different temperatures (1075-1150 °C) to achieve the highest density and mechanical quality factor. Mn-doping resulted in a considerable enhancement of Q
_m
in both planar and thickness vibration modes. In 1.5 mol.% Mn-doped ceramics sintered at 1100 °C, a planar Q
_m
of about 970 and tanδ of 0.88% were obtained. Mn-doping also resulted in decreasing coupling coefficients, piezoelectric charge coefficient, and dielectric constant.