Phase, domain, and microstructures in Sr <sup>2+</sup> substituted low‐temperature sintering PZT‐based relaxor ferroelectrics
Hao Chen, Jie Xing, Jingwen Xi, Tao Pu, Hong Liu, Jianguo Zhu
Abstract
Abstract The Ag‐Pd internal electrode of multilayer piezoelectric ceramics needs to be sintered below 1000°C, and lead wires and components need to be welded with lead‐free solder at 260°C. PNN–PMW–PZT– x Sr piezoelectric ceramics with high Curie temperature ( T c > 260°C) were synthesized at a low sintering temperature (960°C) to meet the requirements of multilayer piezoelectric devices. The relationship between structures (phase, domain, and microstructures) and electrical properties (piezo/ferroelectric properties, and dielectric relaxation) in the Sr 2+ substituted ceramics was investigated. Rietveld refinement and Raman spectra show that Sr 2+ substitution can cause the phase change and increase the force constant of [BO 6 ] octahedron. The piezoelectric response increases with increasing the content of the tetragonal phase ( CTP ) in the rhombohedral‐tetragonal (R‐T) coexisted ceramics. The ceramics with 0.6 mol% Sr 2+ substitution have minimum activation energy for domain wall movement ( E a ) of 0.0362 eV which favors the formation of nanometer‐sized domains, and possess excellent electrical properties ( d 33 = 623 pC/N, d 33 * =783 pm/V, T c =295°C). The higher the CTP , the lower the E a . The lower E a favors the rotation of polarization direction and extension, and is beneficial to the generation of the nanometer‐size domains, resulting in high piezoelectric properties.