Positive temperature coefficient of resistivity effect in Pb-doped KNbO3

KNbO3 is a ferroelectric material with a Curie temperature (T-C) at 415 degreesC, thus giving it the potential to be a material for high-temperature positive temperature coefficient of resistivity (PTCR) applications. In this study, we investigated the PTCR effect in donor-doped KNbO3 ceramics containing 0, 0.1, 0.2, and 03 mol% PbO. The donor-doped KNbO3 ceramics exhibited a PTCR anomaly with a relatively low room-temperature resistivity. The temperature of the tetragonal-to-cubic phase transition (T-C) of the KNbO3 decreased with the amount of added PbO, while the orthorhombic-to-tetragonal phase transition (T-OT) remained unchanged.