Synthesis and dielectric spectroscopic study of lead-free ferroelectric ceramic K0.5Bi0.5TiO3-NaNbO3

We report the synthesis and promising electrical properties of a new lead-free ferroelectric ceramic K0.5Bi0.5TiO3-NaNbO3 (KBT-NN), which can be a candidate of choice for future sensors, FeRAM etc. Mixed-oxide method has been employed to prepare the compound comprising of uniformly distributed grains. Detailed structural analysis revealed its orthorhombic structure with space group Pmc2(1). In-depth analysis of the electrical characterization data revealed a band-gap of 3.11 eV and presence of defects in the bands. Further, ferroelectric phase transition is observed to occur at 395 degrees C. The dielectric properties of the material, investigated over a wide range of frequencies and temperatures, indicate that its ac conductivity depends upon frequency according to Jonscher's power law.