Ultrahigh piezoelectric response in Pb(Ni_1/3Nb_2/3)O₃-PbZrO₃-PbTiO₃ ceramics

To meet the escalating demands for high-performance piezoelectric materials in fields such as modern medical diagnostics, precision manufacturing, etc., we developed a ternary 0.555Pb(Ni_1/3Nb_2/3)O₃-0.145PbZrO₃-0.30PbTiO₃ (PNN-PZ-PT) piezoelectric ceramic located at the tricritical point of rhombohedral, tetragonal and pseudocubic phases. This ceramic, with coexistence of multiple ferroelectric phases, demonstrates an ultrahigh piezoelectric coefficient d₃₃ of 1190 picocoulombs per newton (pC/N) and a large relative dielectric constant ε_r of 9900. Analysis of the domain structure reveals irregular maze-like nanodomains with strong local disorder. These nanodomain structures exhibit excellent local piezoelectric response and polarization switching characteristics, thereby enhancing the alignment of polarization vectors during poling and ensuring the high stability after being poled. The tricritical point composition with disordered nanodomains can significantly enhance the contribution of polarization to macroscopic piezoelectric properties, offering a promising approach for developing ceramics with superior piezoelectricity.