Electrical properties of KTa0.65Nb0.35O3 lead-free ceramics

In the present study, lead-free KTa0.65Nb0.35O3 ceramics were prepared by solid state reaction method using successive calcination steps in order to ensure the complete reaction of the system. The X-ray diffraction analyses of the prepared ceramics have shown the formation of a perovskite structure without any secondary phases. The increase of sintering temperature from 1150 to 1200 degrees C leads to a better densification and decreasing of the Curie temperature (associated with tetragonal-cubic phase transition) closer to the room temperature, i.e. to 290 K. The ceramics sintered at 1200 degrees C exhibits a high tunability (n = 1.6) and a reduced hysteretic behaviour. Due to its moderate permittivity, low losses and field dependence permittivity, the KTa0.65Nb0.35O3 ceramics is suitable candidate for application as tunable capacitors.