Anomalous piezoelectric response due to stabilization of two ferroelectric phases in Zr-modified BaTiO3

The lead-free Ba(Ti1-xZrx)O3 ceramic has shown enhanced piezo-response (d33) in a narrow composition interval (0.01 ≤ x ≤ 0.03) exhibiting the coexistence of two ferroelectric phases. The system presents two electric-field-dependent-property regimes: (i) a low field regime (E < 1.7 kV mm(-1)) where d33 is nearly independent of the poling field, and (ii) E > 1.7 kV mm(-1) for which d33 drops sharply. X-ray diffraction studies revealed that the later phenomenon is related to field driven irreversible structural transformation, which tends to drive the system away from an equilibrium two phase state to a nearly single phase metastable state.