Low-Frequency Dielectric Dispersion and Electrical Conductivity of Pure and La-Doped SrBi2Nb2O9 Ceramics

La-doped Sr1-xLaxBi2Nb2O9 (x = 0, 0.1 and 0.2) ferroelectric ceramics were synthesized by using a solid state reaction method. The low-frequency dielectric dispersion and electrical conductivity were investigated over the frequency range of 100 Hz ~ 1 MHz. With increasing La doping, the Curie temperature Tc decreased and the dielectric peak broadened, while the electrical conductivity increased. The frequency dependences of the real and the imaginary parts of the dielectric constant had a low-frequency dielectric dispersion, which showed a power law relation ε′(ω) ∝ ε″(ω) ∝ ωⁿ-¹ With increasing temperature, the ac conductivities measured at different frequencies tended to merge, which could be described by an Arrhenius relation σ(T) = σo exp(-Ea/kT). With increasing frequency, the ac conductivity was described by using the power-law dependence σ(ω) = σdc + Aωs. The dielectric behavior and ac electrical conductivity of pure and La-doped SBN ceramics were investigated over a wide ranges of the temperature and the frequency. KCI Citation Count: 25