Significant effects of minor chemical composition changes on the structure and property of (Pb 1- y Sr y )(Mg 1/3 Nb 2/3 ) 0.07 Zr x Ti 0.93- x O 3 : z La.

Piezoelectric ceramics with high electrical performances and high Curie temperature ( T c ) act as key materials for numerous electromechanical devices such as transducers and actuators. Herein, we report a systematic investigation on the crystal structure, microstructure and electrical properties of Sr and La co-doped Pb(Mg 1/3 Nb 2/3 )O 3 -PbZrO 3 -PbTiO 3 ceramics with a low Pb(Mg 1/3 Nb 2/3 )O 3 content, namely, (Pb 1- y Sr y )(Mg 1/3 Nb 2/3 ) 0.07 Zr x Ti 0.93- x O 3 : z La. With an increase in the Zr content ( x value) from 0.49 to 0.53, its crystal structure evolved from a tetragonal phase to a rhombohedral phase, leading to not only a morphotropic phase boundary (MPB) at around x = 0.51 but also a monotonously decreasing T c . Meanwhile, a change in either the Sr- or La-doping content ( y and z values, respectively) in the range of y = 0.03-0.07 and z = 0.01-0.03 can slightly deviate the structure of MPB, resulting in a significant effect on its electrical properties. As the best results, the optimal composition of x = 0.51, y = 0.05, and z = 0.02 yielded peak electrical performance, with a related room temperature piezoelectric coefficient ( d 33 ) of 645 pC N -1 , remanent polarization ( P r ) of 33.5 μC cm -2 , coercive field ( E c ) of 8.6 kV cm -1 , and T c of 242 °C. Especially, its piezoelectric properties showed excellent temperature stability, and its d 33 value decreased by only 3% from room temperature to 150 °C. This work not only provides an alternative piezoelectric ceramic with outstanding electrical performance for industrial applications, but also reveals a comprehensive perspective on the composition-structure-property relationship of doped Pb[(Mg 1/3 Nb 2/3 ),Zr,Ti]O 3 , which is helpful for further work on piezoelectric ceramics.