Evolution of Structure, Dielectric and Ferroelectric Properties in Spark Plasma Sintered PLZT (9/65/35) Ceramics

Lanthanum-modified lead zirconate titanate (PLZT) ceramics exhibit excellent ferroelectric and piezoelectric properties, making them attractive for advanced electronic applications. Whereas the fabrication of PLZT is challenging due to the evaporation of PbO at high temperatures. Spark plasma sintering (SPS) enables rapid densification at relatively low temperatures, but the influence of SPS processing on the structural and electrical properties of PLZT ceramics remains insufficiently understood. Herein, dense PLZT (9/65/35) relaxor ceramics were fabricated by SPS. X-ray diffraction with Rietveld refinement revealed a dominant monoclinic phase (C1m1) coexisting with a tetragonal phase (P4mm). Post-annealing effectively tailors the phase composition, promotes grain growth, and modifies defect chemistry. Annealing at 1100 °C yields a refined microstructure, a higher fraction of the M phase, and a lower concentration of lead vacancies, resulting in an enhanced maximum dielectric permittivity (up to ~12195), maximum polarization (up to ~45 μC/cm 2 ) and field-induced strain (0.193% at 30 kV/cm). This work establishes a process–structure–property relationship for spark plasma sintered PLZT ceramics, demonstrating that controlled post-annealing is critical for optimizing phase assemblage, defect equilibrium, and microstructure to achieve superior electrical properties.