Abstract
This paper focuses on the size effect of lead zirconate titanate. Pb(Zr0.4Ti0.6)O3 (PZT40) nanoparticles with different sizes were prepared by a sol-gel method. The crystal size and structure were determined by X-ray diffraction. As a result, the c/a ratio or tetragonality approached unity with decreasing particle size. Raman spectra of PZT40 nano-particles with various sizes were observed and we found that there is a decrease in the soft mode at around 35nm, suggesting the existence of critical size for the PZT40 particles. The temperature dependence of Raman spectra clearly revealed that Tc for PZT40 nano-particles shifted toward lower temperatures due to the size effect. The intrinsic dielectric constants of PZT40 nano-particles calculated by LST relation increased with decreasing the particle size. These results prove that the Raman scattering is a powerful tool to investigate the ferroelectric materials.
