Structural and dielectric studies of lead-free ceramics: Na1/2Y1/2TiO3

The polycrystalline samples of Na_1/2Y_1/2TiO₃ were prepared by the mixed-oxide method. A preliminary X-ray structural analysis was shown to exhibit the formation of a single-phase compound with an orthorhombic structure. Microstructural analysis by scanning electron microscopy (SEM) exhibits well defined grains distributed uniformly through out the sample suggesting the compactness and homogeneity of the sample. Detailed studies of dielectric properties of Na_1/2Y_1/2TiO₃ in a wide frequency range (102–106 Hz) at different temperatures (31–500°C) show a dielectric anomaly at 105°C, which may be related to a ferroelectricparaelectric phase transition as suggested by hysteresis loop at room temperature. An ac conductivity (σ _ac) of the material is mainly governed by the polaron hopping mechanism, which is also influenced by both frequency and temperature. The activation energy was obtained from the plot of temperature with a.c. conductivity.