Influence of vanadium doping on the processing temperature and dielectric properties of barium bismuth niobate ceramics

Barium bismuth vanadium niobate, BaBi2(Nb1−xVx)2O9 (0 ≤ x ≤ 0.1) ceramics were fabricated from the powders prepared via solid state reaction route. The single phase layered perovskite structure was preserved up to 5 at% (x = 0.05) of vanadium. The addition of V2O5 substantially improved the sinterability associated with high density (96%) which was otherwise difficult in the case of pure BaBi2Nb2O9 (BBN). The sintering temperature was significantly reduced from 1100 to 900 °C. The scanning electron microscopic (SEM) studies revealed the transformation of a porous microstructure to a well-packed platy grained with negligible inter-granular porosity. The dielectric constant of BBN ceramics at both room temperature and in the vicinity of the temperature of dielectric maximum (Tm) has increased significantly with increase in vanadium content and the loss remained almost constant. The Tm increased with increase in V2O5. For instance, there was an upward shift of about 25 °C in Tm for 5 at% (x = 0.05) vanadium-doped BBN. Interestingly, the diffuseness (γ) in the phase transition was found to decrease with increase in vanadium doping level.