Tuning polarization of sodium niobate-based ceramics by introducing Sr(Fe0.5Nb0.5)O3

NaNbO3 (NNO) is one of few Pb-free antiferroelectrics. But it commonly shows ferroelectricity due to the irreversible transition from antiferroelectric to ferroelectric. By adding Sr(Fe0.5Nb0.5)O-3 (SFN), a novel dielectric ceramic (1 - x)NNO- xSFN has been prepared by a conventional solid reaction method. The ceramic is the pure phase with x up to 0.15. With increasing x, the polarization-electric relation varies from ferroelectric to antiferroelectric like and then to linear like, indicating that the polarization varies from parallel to antiparallel and then to randomly orientated. The electrical response of the ceramics is further analyzed by the normalizations of impedance and electrical modulus, which suggests enhanced electrical heterogeneity, reduced grain resistance, and decreased thermal activation energy with increasing x.