Size effect for lead zirconium titanate nanopowders with Pb(Zr0.3Ti0.7)O3 composition

This paper focuses on the size effect for lead zirconate titanate. Pb(Zr0.3Ti0.7)O-3 (PZT30) nanopowders with different sizes were prepared by chemical solution deposition. The crystal sizes of the prepared samples were determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The crystal structures were identified by XRD. The c/a ratio or tetragonality for PZT30 nanocrystals was close to I with decreasing crystal size. Raman spectra for PZT30 nanocrystals with various grain sizes have been observed to, show the sudden decrease in the soft mode frequencies E(ITO) and A(1) (ITO) at around 25 nm, suggesting the existence of the critical size for PZT30 nanopowders. The intrinsic dielectric constant which was calculated from the phonon mode shift by using the Lyddane-Sachs-Teller (LST) relation increased with decreasing crystal size. The temperature dependence of Raman spectra clearly revealed that T-c for PZT30 nanopowder shifted due to the size effect.