Piezoelectric response hysteresis in the presence of ferroelastic 90° domain walls

Piezoelectric response hysteresis curves of Pb(Zr0.2Ti0.8)O3-based capacitors have been measured by piezoresponse force microscopy. The piezoelectric coefficient d33 was found to vary considerably depending on the position of the probing tip on the top electrode for films possessing a c∕a∕c domain structure. d33 values up to 125pm∕V, which is twice the theoretical value for a clamped film, have been measured. The spatial variations of the piezoelectric response amplitude is explained by a local movement of ferroelastic 90° a domains. This work experimentally proves the local enhancement of the polarization near the 90° wall boundaries, as predicted by Ishibashi et al. [Jpn. J. Appl. Phys. 44, 7512 (2005)].