Peculiar dielectric behaviors of (Na1/2Bi1/2) 0.87Pb0.13TiO3 thin films

Abstract

PbTiO3-doped sodium bismuth titanate (Na1/2Bi 1/2)1-x PbxTiO3 of perovskite structure is one of the best-known piezoelectrics/ferroelectrics. However, it has not been properly investigated in any thin-film forms. In this study, the dielectric properties of (Na1/2Bi1/2) 0.87Pb0.13TiO3 thin films synthesized via a sol-gel route were investigated. They exhibit a strong frequency dispersion of the dielectric permittivity at relatively high frequencies, which is shifted to lower frequencies with increasing temperature. The electrical behavior can be fitted using Jonscher's universal law for dielectric relaxation. The peculiar dielectric behaviors observed can be ascribed to the coexistence of two different dielectric phases in the films, which is believed to be associated with the growth of the local Pb2+TiO3 nanoclusters upon substitution of Pb2+ for Na+/Bi3+ in the (Na1/2Bi1/2)1-xPbxTiO3 films. © 2006 The American Ceramic Society.