Negative in-plane Poisson's ratio in [001]-textured PMN-PZT ceramics

[001]-textured 0.4P(Mg1/3Nb2/3)O3-0.25PbZrO3-0.35PbTiO3 (PMN-PZT) ceramics were fabricated by templated grain growth using 3 vol. % BaTiO3. Full matrices of dielectric (εij), elastic (sij, cij), and piezoelectric (dij) parameters were obtained by the resonance–antiresonance method. The ceramics exhibit a quasi-static piezoelectric coefficient d33 of 1490 pC/N and an electromechanical coupling factor k33 of 0.92, approaching the performance levels of piezoelectric single crystals. Notably, the textured PMN-PZT demonstrates an in-plane negative Poisson's ratio of ν12 = −0.13, representing a strong auxetic behavior that has been experimentally confirmed through direct strain–stress measurement. This distinctive characteristic is further corroborated by both laser scanning vibrometer and finite element analysis. Theoretical interpretation suggests that the negative Poisson's ratio stems primarily from stress-induced polarization rotation along the ⟨110⟩ direction. In [001]-textured ceramics, the transverse direction inherently contains this orientation, typically resulting in a low or negative Poisson's ratio. This abnormal Poisson's ratio property may affect device design approaches for transducers, sensors, and energy harvesting applications.