Temperature dependent dielectric response and conduction mechanism of nickel doped bismuth ferrite nanoparticles

摘要

BiFe_(0.93)Ni_(0.07)O_3 sample was prepared through ethylene glycol based sol gel method. In order to understand the conduction mechanism, the temperature dependent dielectric properties have been explored in detail. The general dielectric trend that is a decrease in dielectric constant with rise in frequency has been observed. The obtained behavior of ac conductivity follows the Jonscher's power law and found fitted well. The frequency exponent (s) is found to reduce with increase in temperature. In this way, the variation of frequency exponent with temperature recommended that the correlated barrier hopping (CBH) model is appropriate to identify the conduction process in the temperature range of 300-400 K. The minimum hopping distance was computed and observed to be of the order of 10~(-10) m. The density of states at the Fermi level and binding energy are evaluated from the ac conductivity data. The change in ac conductivity with temperature follows the Arrhenius equation. The activation energy has also been evaluated.