Effect of 90° domain movement on the piezoelectric response of patterned $PbZr0.2Ti0.8O3∕SrTiO3∕Si$ heterostructures

The converse longitudinal piezoelectric responses of $PbZr0.2Ti0.8O3∕SrTiO3∕Si$ heterostructures have been studied for continuous films and for islands patterned by focused ion beam milling (typical dimension is $1×1×1μm$⁠). The intrinsic piezoelectric response of the island with an immobile polydomain structure is modeled using finite element analysis. The difference between the results of experimental measurement and modeling is explained by an extrinsic contribution to the piezoresponse from 90° domain movement. The contribution of 90° domain movement to the total piezoresponse is shown to be greatly enhanced in the patterned islands, and leads to an effective piezoelectric coefficient $(∼400pm∕V)$ which is five times larger than the theoretical bulk single domain value.