Stress-induced and thermal-induced depolarization studies along with X-ray diffraction were performed on lead zirconate titanate ferroelectrics of different compositions, PbZr0.52Ti0.48O3 (PZT 52/48) and PbZr0.95Ti0.05O3 (PZT 95/5). Specimens were shock loaded perpendicular to the polarization vector. It was found that the polarity of the stress-induced charge released by PZT 52/48 and 95/5 was opposite to the polarity of the charge generated due to the piezoelectric effect. PZT 52/48 was only partially (45%) depolarized under 1.5 ± 0.1 GPa mechanical compression, as opposed to PZT 95/5 which was fully depolarized. The experimental results indicate that the stress-induced depolarization mechanisms are different for these two compositions. PZT 52/48 is transformed to a state with lower polarization, while PZT 95/5 undergoes a phase transition to a non-polar antiferroelectric phase.

Ceramic niobium modified 95/5 lead zirconate-lead titanate (PZT) undergoes a pressure induced ferroelectric to antiferroelectric phase transformation accompanied by an elimination of polarization and a volume reduction. Electric field and temperature drive the reverse transformation from the antiferroelectric to ferroelectric phase. The phase transformation was monitored under pressure, temperature, and electric field loading. Pressures and temperatures were varied in discrete steps from 0 MPa to 500 MPa and 25 °C to 125 °C, respectively. Cyclic bipolar electric fields were applied with peak amplitudes of up to 6 MV m−1 at each pressure and temperature combination. The resulting electric displacement–electric field hysteresis loops were open “D” shaped at low pressure, characteristic of soft ferroelectric PZT. Just below the phase transformation pressure, the hysteresis loops took on an “S” shape, which split into a double hysteresis loop just above the phase transformation pressure. Far above the phase transformation pressure, when the applied electric field is insufficient to drive an antiferroelectric to ferroelectric phase transformation, the hysteresis loops collapse to linear dielectric behavior. Phase stability maps were generated from the experimental data at each of the temperature steps and used to form a three dimensional pressure–temperature–electric field phase diagram.

Niobium doped lead zirconate titanate (95/5 NbPZT) undergoes a hydrostatic pressure induced ferroelectric rhombohedral to antiferroelectric orthorhombic phase transformation (FE-AFE). This work reports on the experimental characterization of the large field dielectric response to unipolar electric field as it passes through the forward and reverse FE-AFE transformations. The poled ceramic was hydrostatically depoled by driving the FE-AFE phase transformation and stress-strain and stress-electric displacement responses were measured. After this initial characterization, specimens of 95/5 NbPZT were subjected to unipolar electric field loading at different hydrostatic pressure levels. Electric field was varied from zero to 1 MV/m at a series of fixed pressure levels between zero and 550 MPa. This resulted in minor hysteresis loops with the area inside the loops dependent on both pressure and electric field amplitude. Two different slopes were taken from the D-E loops, identified as the small field and large field slopes. Each changed with pressure and displayed distinct jumps at the forward and reverse FE-AFE phase transformations. The area within the loops in the ferroelectric regime, attributed to domain wall motion, increased as pressure was increased and dropped abruptly as the material passed through the pressure induced phase transformation.

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