Structural Description of the Macroscopic Piezo- and Ferroelectric Properties of Lead Zirconate Titanate

An in situ structural description of the origin of the ferroelectric properties as a function of the applied electric field $E$ was obtained by synchrotron x-ray diffraction. A setup was used to average the effects of the preferred orientation induced by the strong piezoelectric strain and solve in situ the crystal structure as a function of the applied electric field. Hence, we were able to describe the microscopic origin of the macroscopic ferro- and piezoelectric properties of the most widely used ferroelectric material, lead zirconate titanate.

Figure 1

(a) 45°-scattering geometry used in the experiment. Note that the effects texturing (${\eta }_x={\eta }_y$) induced by remanent strain are minimized in such a configuration. For better visualization the field induced strain is exaggerated. (b) The ${200}_t/{002}_t$ tetragonal reflection pair intensity for a PZT sample in a capillary (blue line), for poled sample with 0°-scattering geometry (black line), and for a poled sample with 45°-scattering geometry (red line). The preferred orientation is characterized by a strong deviation of the intensity ratio ($\psi =0°$).

Figure 2

Influence of the applied electric field on the ${002}_t$ reflection, (a) from 0 to $2.2\mathrm{kV}/\mathrm{cm}$, (b) from 2.2 to $0\mathrm{kV}/\mathrm{cm}$, (c) from 0 to $-2.2\mathrm{kV}/\mathrm{cm}$, and (d) from $-2.2$ to $0\mathrm{kV}/\mathrm{cm}$. The insets show the position in the corresponding hysteresis cycle (HC) for the same range of electric field (1)–(4).

Figure 3

(a) Rietveld refinements of PZT at $0\mathrm{kV}/\mathrm{mm}$ and (b) $1\mathrm{kV}/\mathrm{mm}$. The difference plot has same scale. The vertical tick marks indicate the calculated positions of the $P4mm$ phase (top) and $Cm$ phase reflections (bottom). The insets show the corresponding HC for the same range of electric field (1)–(4).

Figure 4

(a) Monoclinic-tetragonal phase fraction (%) and (b) isotropic mean square displacement of the lead atom in the monoclinic phase $B_{\mathrm{iso}}(\mathrm{Pb}{)}_m$. The inset shows the corresponding HC for the same range of electric field (1)–4).