Dielectric relaxation characteristics of bismuth zinc niobate pyrochlores containing titanium

Dielectric relaxation studies have been made in pyrochlore (Bi1.5Zn0.5)(Zn0.5-x/3TixNb1.5-2x/3)O7 ceramics where 0≤x≤1.5. The measurements of dielectric constant (ε) and dielectric loss (tan δ) are made in the frequency range (1-1000 kHz) at various temperatures from -200 to 200 deg. C. Dielectric constant have the highest value of 215 at the x=1.5 composition. Permittivity peaks with obvious frequency dispersion were observed and with the increase of the Ti content, the temperature of the permittivity maximum of each one is shifted to lower temperatures. The results indicated that the dielectric dispersion occurs in low temperature. The relaxation behaviour is characterised in the present paper, the effect of Ti on the dielectric relaxation behaviour and the physical mechanism giving polarization is briefly discussed