Controllable piezoelectricity of Pb(Zr0.2Ti0.8)O3 film via in situ misfit strain

The tetragonality (c/a) of a PbZr0.2Ti0.8O3 (PZT) thin film on La0.7Sr0.3MnO3/ 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PMN-PT) substrates was controlled by applying an electric field on the PMN-PT substrate. The piezoelectric response of the PZT thin film under various biaxial strains was observed using time-resolved micro X-ray diffraction. The longitudinal piezoelectric coefficient (d33) was reduced from 29.5 to 14.9 pm/V when the c/a ratio of the PZT film slightly changed from 1.051 to 1.056. Our results demonstrate that the tetragonality of the PZT thin film plays a critical role in determining d33, and in situ strain engineering using electromechanical substrate is useful in excluding the extrinsic effect resulting from the variation in the film thickness or the interface between substrate.