Densification and frequency dielectric response (102 to 109 Hz) of ferroelectric K(Ta0.5Nb0.5)O3 ceramics

The frequency dielectric response in K(Ta0.5Nb0.5)O3 ceramics (KTN) is investigated over the temperature range 280 to 450 K and over a wide range of frequency (102 to 109 Hz). The KTN ceramics are sintered using Li2CO3 as an addition, allowing liquid phase sintering. Dielectric measurements are performed on two samples:a fast fired sample and a conventionally fired one. The ferroelectric-paraelectric transition occurs at Tc ≈ 380 K; it is a first-order transition. Two dielectric dispersions are observed: a polydispersive low frequency one (102 to 105 Hz) and a high frequency relaxation (108 to 109 Hz). The latter is explained on the basis of correlation chains or correlation volumes in a double potential well model.