Effect of niobium-doping and grain size on the dielectric properties of lead barium zirconate titanate relaxors

The relationship between grain size and dielectric properties for (Pb0.65Ba0.35)(Zr0.70Ti0.30)O-3, or PBZT, modified with various amounts of niobium oxide was studied. Sintering conditions were controlled to produce samples with grain size ranging from 2 to 15 mum. The 0.5% and 1% Nb-doped PBZT showed rapid grain growth when compared to undoped PBZT and those with higher Nb concentration. Dielectric measurement results showed that the dielectric maxima (K-max) of PBZTs increased monotonically with increasing grain size without shifting the temperature of dielectric maximum (T-max). On the other hand, the application of DC bias caused a slight decrease of both K-max and T-max.