Temperature Sensitive Conductivity Studies of NBT-Based Lead-Free Ternary System

The frequency and temperature dependence electrical conduction characteristics of a lead-free 0.78NBT-0.2ST-0.02BT ternary system were investigated by impedance spectroscopy. Variation of real part of conductivity with frequency reveals a frequency independent and a dispersive region obeying Jonscher power law. The relatively higher values of S-parameter in the mid temperature range envisage the presence of localized relaxation or hopping of the charge carriers. The activation energies calculated from the temperature dependent hopping frequency and dc conductivity, portray the increase of unsuccessful hops of the charge carriers with increase in temperature according to the Jump relaxation model. Interestingly the conductivity values could be curbed by introduction of BT in to NBT-ST. The collapsing of the scaled conductivity spectrum in to a single master curve depicts the temperature independent conduction relaxation mechanism. (paper)