Physical Properties of the K0.5Na0.5NbO3 Compound Doped With Li, La, and Ti in Concentration Lower Than 1.3 mol%

Abstract

Physical properties of the K_0.5Na_0.5NbO₃ (KNN) system doped with less than 1.3 mol% of Li⁺, La³⁺, and Ti⁴⁺ ions were studied. These samples were prepared by a mixture of oxides and carbonates using high-energy milling and solid-state reactions. The sample KNNLa0.75 showed an orthorhombic phase, and the rest showed a mixture of monoclinic and orthorhombic phases. Ion doping induced an increase in the grain size, and improved the ferroelectric and pyroelectric properties, decreasing leakage currents. The thermal diffusivity decreases with doping and differential scanning calorimetry measurements allowed the identification of crystalline transition temperatures from orthorhombic‒tetragonal, monoclinic‒tetragonal, and tetragonal‒cubic phases.