Microwave dielectric properties of the Ag1-xLixNbO3 (x=0 divided by 0.06) ceramics

Dielectric properties of the AgNbo(3) (AN) and Ag1-xLixNbO3 ceramics with x = 0.02, 0.04, 0.06 were investigated at microwaves (MW, 36 GHz) in the tem perature range of 100 + 570 K, including the phase transitions in AN at 340 K (weak ferroelectric - antiferroelectric) and at 530K (antiferroelectric - antiferroelectric). The results of MW measurements were compared with radio frequency and IR dielectric properties. No significant dielectric dispersi on was observed. The anomalies of epsilon'(T) and epsilon"(T), correspondin g to the phase transitions, were observed in AN and in Ag1-xLixNbO3. The Li additives for x less than or equal to 0.04 do not result in significant ch ange of the MW dielectric properties. The ceramic with x = 0.06 shows a muc h lower MW epsilon' below 250 K and a sharp step-like anomaly of epsilon'(T ) at approximate to 425 K. This indicates a significant change of the struc ture which is also confirmed by the pronounced change in the IR reflectivit y.