Oxygen vacancy related relaxation and conduction behavior in (1-x) NBT-xBiCrO₃ solid solution

Abstract

The ac-conductivity measurements carried out on (1-x)NBT-xBiCrO₃ solid solution in the radio frequency range. The conductivity measurements suggest that with increase in BiCrO₃ content the electrical conductivity of sodium bismuth titanate (Na_0.5Bi_0.5TiO₃) (NBT) increases. For x=0.10 and 0.15 two relaxation behaviors are observed, related to long range conduction and short range hopping of defects. Activation energy calculated from dielectric relaxation as well as conductivity data reveals that both the processes are due to oxygen defects formed by substitution of chromium at titanium site. A reasonable decrease in the conductivity and dielectric loss were observed after oxygen annealing of the samples. Presence of relaxation peaks even after oxygen annealing suggests that relaxation is mainly by extrinsic oxygen defects produced due to substitution of chromium.