Zr-shift at the origin of the exceptional piezoelectric properties of PbZr0.52Ti0.48O3

In spite of intensive experimental and theoretical studies, no model at the atomic scale has been proposed to explain the large piezoelectric effect in PbZr0.52Ti0.48O3 (PZT) compared to the low piezoelectric response in the simple end-member lead titanate PbTiO3. X-ray absorption spectroscopy (XAS) appears as the technique of choice not only to clarify the role of Zr, but also to quantify the Zr displacement through the Ferroelectric-Paraelectric (F-P) transition. We clearly show evidence of the polar character of the Zr-atoms in PZT with a Zr-shift which will produce a small polarization. Such an atomic configuration for one type of atoms leads to relatively easy switching, i.e., relatively low electric field to align the Zr-polar atoms, which will create a favorable energetic situation for the cooperative switching of the strongly polar Ti-O dipole and would therefore account for the large piezoelectric effect in PZT.