Frequency dependent dielectric, modulus, impedance and AC conductivity study of Poly Vinyl Alcohol with 25 vol.% of Yttrium modified Barium Zirconium Titanate ceramic have been investigated. The single phase Yttrium modified Barium Zirconium Titanate ceramics have been synthesized by conventional solid state route. The relaxation mechanism of dielectric and modulus study is due to the segmental motion of polymer chain along with the dipole orientation of ceramic in the polymer composite. The Nyquist plot of impedance shows two semicircles, which represents the bulk and interfacial effect of polymer composites. The activation energy decreases with incorporation of higher Yttrium modified Barium Zirconium Titanate ceramics in the polymer matrix due to the even distribution of ceramic in the polymer composite. The different activation energy obtained from conduction and relaxation of the composite indicates that various mechanisms are involved in the conduction and relaxation process.

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Bismuth sodium titanate, Bi 0•5 Na 0•5 TiO 3 (BNT) is considered to be an excellent candidate for a key material of lead-free dielectric ceramics. In this study, we propose the dielectric and optical study of single phase BNT powder prepared by solid-state reaction route. The phase formation and structural study were done by X-ray diffraction (XRD) which shows well developed crystallite with a pure perovskite phase. The ceramic was sintered at different temperatures from 1050 • C to 1175 • C to study the effect of sintering temperature on the morphology and density. It was found that the sample sintered at 1150 • C shows the highest density. The microstructure of the ceramic was investigated by scanning electron microscopic (SEM) technique. The temperature-dependent dielectric study of the sample sintered at 1150 • C was done in the frequency range of 50 kHz-1 MHz which shows a diffuse phase transition. The piezoelectric constant (d 33) was found to be 41 pCN −1. The P-E hysteresis loop confirms the ferroelectric behaviour in the ceramic. The UV-Vis spectrum indicated that the Bi 0•5 Na 0•5 TiO 3 ceramic has an optical band gap of 2•94 eV.