Field‐Forced Antiferroelectric‐to‐Ferroelectric Switching in Modified Lead Zirconate Titanate Stannate Ceramics

Electric‐field‐forced antiferroelectric‐to‐ferroelectric phase transitions in several compositions of modified lead zirconate titanate stannate antiferroelectric ceramics are studied for ultra‐high‐field‐induced strain actuator applications. A maximum field‐induced longitudinal strain of 0.85% and volume expansion of 0.95% are observed in the ceramic composition Pb_0.97La_0.02(Zr_0.66Ti_0.09Sn_0.25)O₃ at room temperature. Switching from the antiferroelectric form to the ferroelectric form is controlled by the nucleation of the ferroelectric phase from the antiferroelectric phase. A switching time of <1 μs is observed under the applied field above 30 kV/cm. The polarization and strains associated with the field‐forced phase transition decrease with increasing switching cycle, a so‐called fatigue effect. Two types of fatigue effects are observed in these ceramic compositions. In one, the fatigue effects only proceed to a limited extent and the properties may be restored by annealing above the Curie temperature, while in the other, the fatigue effects proceed to a large extent and the properties cannot be restored completely by heat treatment. Hydrostatic pressure increases the transition field and the switching time. But when the applied electric field is larger than the transition field, the induced polarization and strain are not sensitive to increasing hydrostatic pressure until the transition field approaches the applied field.