Dielectric and electrical properties of LiNbO3 ceramics

Li1−xNb1+x/5O3 (where x = 0, 0.025, 0.045, 0.075) ferroelectric ceramics were prepared by the solid-state reaction method; X-ray diffraction patterns indicate that single phase was formed for pure LN ceramics. The electrical behavior of the ceramics was studied by impedance spectroscopy technique in the 300–1000 °C temperature range. Impedance analysis was performed revealing a conductivity data which fitted in the modified power, σac(ω) = A · ωn1 + B · ωn2 and evidence of two types of conduction process. The low-frequency conductivity is due to long-range ordering (near frequency-independent) and high-frequency conduction due to the localized orientation hopping mechanism. The static conductivity is determined for all compositions from Cole–Cole diagrams, and the evolution vs temperature is studied as a function of the Li/Nb ratio.