Improvement of piezoelectric properties of PZT‐based low‐temperature‐sintered ceramics through heterovalent ion doping

Abstract

AbstractThe piezoelectric properties of Pb(Zr,Ti)O3 (PZT)‐based piezoceramics can be improved by doping with heterovalent ions at the A/B sites. Nd3+ ions were codoped at the A site and Ta5+ ions were doped into the B site of Pb(Zr0.5Ti0.5)(Mg0.5W0.5)(Ni1/3Nb2/3)O3 (xNd2O3‐PZTMWNN) ceramics sintered at a low temperature of 940°C. The number of Ta5+ ions at site B remained constant, whereas the number of Nd3+ ions at site A changed. The degree of deviation from the Curie–Weiss law (∆Tm) and the degree of diffuseness of the ferroelectric relaxors (γ) have a direct and close relationship. Combined analysis of the grain size, phase structure, domain structure, and activation energy (Ea) for domain wall movement was used to understand the mechanism of the piezoelectric improvement in PZT‐based ceramics. The high proportion of the tetragonal phase in the coexisting tetragonal–rhombohedral phases is closely related to the low Ea, which promotes domain rotation and leads to high piezoelectricity. The xNd2O3–PZTMWNN (x = 2.0, 2.5) ceramics have a very low Ea, but the clamping effect caused by the fine grain boundaries hinders the motion of the domain wall. The xNd2O3–PZTMWNN (x = 1.0) ceramics with low Ea, striped nanodomains, and large grains exhibited the highest piezoelectric activity.