Structure and electrical properties of cold-sintered strontium-doped potassium sodium niobate

Abstract

Cold sintering is an attractive method for sintering ferroelectric ceramics at temperatures at or below 300 °C. While we can practically obtain bulk samples by introducing a transient liquid and applied pressure, the mechanisms of sintering and final functional properties of cold-sintered ceramics are far from being understood. Here, we investigate the influence of grain size and sintering parameters on the microstructure and ferroelectric properties of 0.5 % Sr-doped K0.5Na0.5NbO3 ceramics. By comparing with the conventionally-sintered samples, we find that cold-sintered ceramics have higher dielectric permittivity and lower dielectric losses, which we attribute to smaller grains and higher relative density. Using atomic-scale analysis, we point out the presence of numerous lattice dislocations that likely act as pinning sites and thus inhibit any significant polarization-switching behaviour. Due to the slim P–E loop and high dielectric breakdown fields of the cold-sintered ceramics we consider its potential for energy storage applications.