Strain-gradient-induced polarization or flexoelectricity was investigated in unpoled soft lead zirconate titanate ͑PZT͒ ceramic where the texture symmetry ϱϱ m forbids macropiezoelectricity. Even under high strain gradient (1 m Ϫ1 ) the induced polarization is small (1.6 C/m 2 ) at 20°C. Higher strain gradients induce ferroelastic poling and an additional extrinsic contribution to the flexoelectric coefficient 12 raising the value from 0.5 to 2.0 C/m. Cooling through the Curie point (T C )

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... maximum stress ͑80 MPa͒ where the peak permittivity (ϳ20 000) could raise 12 to 20 C/m, the equivalent electric field is still only ϳ1 kV/m, inadequate to achieve significant ferroelectric poling. The situation may be different in thin PZT films where much larger strain gradients can occur.