Effect of Bi-doping on the electrophysical properties of sodium niobate solid solutions

Introduction of dopants is a classic method for modifying the properties of materials, in particular, complex oxides of the perovskite family with the general formula ABO3. Ions located in positions A and/or B are substituted. In this case, their valence can coincide with the valence of the basic ion (isovalent substitution) or differ (heterovalent substitution). Sodium niobate (NaNbO3) is a convenient basis for producing ferroelectric solid solutions. Doping changes the properties of sodium niobate in a wide range, allowing the production of functional materials for various applications. In this paper, the effect of Bi3+ doping upon substitution of niobium ion Nb5+ on the structure and electrophysical properties of sodium niobate is studied. It has been shown that such compositions are characterized by a significant increase in electrical conductivity with increasing the doping concentration, a decrease in the Curie temperature, and a change in the grain structure. The dopant concentration is more than 10 mol. % leads to the formation of some secondary phases.