Electrical microstructure properties of 0.9KNbO3−0.1BaNi12Nb12O3−δ electroceramic

The electroceramic of 0.9KNbO3−0.1BaNi12Nb12O3−δ (KBNNO) is synthesized using solid state reaction and its electrical microstructure properties are investigated using impedance spectroscopy. KBNNO exhibits negative temperature coefficient of resistance of - 0.283°C−1 at 400 °C and the grain boundaries dominate its electrical properties. The conductivity is found to increase with the onset of ferroelectric to paraelectric phase transition. The possible underlying mechanism responsible for increase of conductivity with the onset of phase transition is discussed. The activation energy of conductivity is calculated to be 0.61eV, indicating proton ion conduction in this electroceramic and the conduction mechanism can be described by using large polaron model. Present study suggests that KBNNO could be a prospective material for many noble applications such as solid oxide fuel cell, hydrogen sensing, and negative temperature coefficient thermistor for temperature compensation and temperature sensor etc.