Strains and Polarization During Antiferroelectric–Ferroelectric Phase Switching in Pb 0.99 Nb 0.02 [(Zr 0.57 Sn 0.43 ) 1−y Ti y ] 0.98 O 3 Ceramics

The electric field‐induced antiferroelectric‐to‐ferroelectric phase transition is investigated through detailed measurements of electric polarization P , longitudinal strain x 33 , and transverse strain x 11 developed under applied electric fields in a series of Pb 0.99 Nb 0.02 [(Zr 0.57 Sn 0.43 ) 1− y Ti y ] 0.98 O 3 ceramics with compositions close to the antiferroelectric/ferroelectric phase boundary. It is found that the volume expansion, expressed as ( x 33 +2 x 11 ), at the antiferroelectric‐to‐ferroelectric phase transition remains ∼0.4% regardless of the composition in the range of 0.060≤ y ≤0.075. However, the induced ferroelectric phase in compositions y ≥0.069 becomes metastable and the ferroelectric‐to‐antiferroelectric phase transition does not occur during the unloading of the applied field. This reverse phase transition occurs partially when electric fields with reversed polarity are applied. As a consequence, the switchable mechanical strains in compositions y ≥0.069 are significantly reduced as y (Ti content) increases even though the switchable polarization remains at a high value.