Structure and dielectric properties of Ti-doped KNN ceramics

Abstract

The work is devoted to investigation of the influence of the technology for producing potassium sodium niobate ceramics with an acceptor impurity Ti4+ on its structure and dielectric properties. The aim of the work was to determine ways to obtain a single-phase composition of doped ceramics and the role of the TiO2 modifying impurity. It is shown that the substitution of niobium by titanium for preserves the cubic shape of potassium sodium niobate grains, increases dielectric losses and causes significant migration polarization. The latter leads to the fact that the maximum temperature dependence of the dielectric permittivity at low frequencies is not observed for the studied ceramics. The shift of the phase transition temperature caused by doping is not observed. In all samples, despite the heterogeneity of the elemental composition and grain structure, the phase transition temperature corresponds to the phase transition temperature of pure potassium sodium niobate ceramics.

Keywords

• sodium potassium niobate
• ferroelectric solid solutions
• dielectric permittivity
• acceptor dopants
• phase transition