Probing the intrinsic and extrinsic origins of piezoelectricity in lead zirconate titanate single crystals

The physical origin of the piezoelectric effect has been the focus of much research work. While it is commonly accepted that the origins of piezoelectricity may be intrinsic (related to the change of lattice parameters) and extrinsic (related to the movement of domain walls), their separation is often a challenging experimental task. Here in situ high-resolution synchrotron X-ray diffraction has been combined with a new data analysis technique to characterize the change of the lattice parameters and domain microstructure of a PbZr_1-xTi_xO₃ (x = 0.45) crystal under an external electric field. It is shown how ‘effective piezoelectric coefficients’ evolve upon the transition from purely ‘intrinsic’ effects to ‘extrinsic’ ones due to domain-wall motion. This technique and corresponding data analysis can be applied to broader classes of materials and provide important insights into the microscopic origin of their physical properties.