Electrical and dielectric properties of Nd-doped SrBi2Ta2O9 ceramics

Combination of molten-salt and calcination techniques was used to synthesize Nd-doped SrBi2Ta2O9 (x = 0, 0.02, 0.05 and 0.1) ceramic powders. The prepared powders were uniaxially pressed and sintered at 1200?C for 6 h. The suggested approach allows obtaining pure products without secondary phases, while the Nd content slightly affected the unit cell parameters. The diffusivity of the dielectric maximum increases and the Curie temperature decreases with the increase of Nd concentration. The non-overlapping small polaron tunneling remained the predominant conduction process. Within the temperature range from 300 to 450?C, both the bulk grain and the grain boundary resistances were determined from the Nyquist plots. It was shown that the grain boundary resistivity decreases with temperature owing to the charge carriers? movement and the grain boundary and grain resistivities decrease when Nd was introduced in the SrBi2Ta2O9 structure.