Piezoelectricity and Thermophysical Properties of Ba(0.90)Ca(0.10)Ti(0.96)Zr(0.04)O(3) Ceramics Modified with Amphoteric Nd(3+) and Y(3+) Dopants

Lead-free barium calcium titanate zirconate (BCTZ) ceramics doped with a single rare-earth element generally exhibit excellent piezoelectric properties. However, their electrical properties deteriorate at an excessive dopant content, limiting their application. In this study, amphoteric neodymium (Nd(3+)) and yttrium (Y(3+))-codoped BCTZ-NYx ceramics were synthesized via a solid-state reaction at 1240 °C. The influences of the Y(3+) content (x) on the structural features, electrical properties, mechanical properties, and thermophysical properties were investigated. At a small x (<0.18 mol%), Y(3+) could enhance the fracture strength and electrical properties by eliminating oxygen vacancies, defect dipoles, and/or structural defects. However, the outstanding performance deteriorated with excessive x. Additionally, the mechanism of the defect chemistry at different x was deduced. At an yttrium content of 0.18 mol%, the ceramic exhibited high piezoelectricity and ferroelectricity with low domain-switching activation energy (E(a) = 0.401 eV), indicating that it could replace commercial lead-based piezoelectric ceramics.