Material properties of bismuth layered ferroelectrics and lead zirconate titanate piezoelectric ceramics

The material properties of bismuth layer-structured ferroelectrics (BLSFs) and lead zirconate titanate (PZT) piezoelectric ceramics have been investigated. The fatigue strength of the PZT sample was higher than that of the BLSF. The electrical properties were altered as a result of cyclic loading. The piezoelectric constant (d33) and electromechanical coupling coefficient (k33) decreased with increasing applied load for both piezoelectric ceramics. However, the rate of reduction for the BLSF sample is smaller than that for the PZT ceramic. This different rate is attributed to the different material characteristics. During cyclic loading, the strain value increased with increasing cycle number for the PZT sample. Like the PZT ceramic, the strain value increases for the BLSF but the back strain occurred after the cyclic loading was conducted for certain period of times. This different strain behavior is influenced by the different domain switching characteristics and this was clarified from the respective strain–electric field relationships.