The influence of Ti-nonstoichiometry in Bi0.5Na0.5TiO3

The influence of Ti-nonstoichiometry in BNT was investigated using XRD, SEM/EDX and electrical measurements. It is shown that nonstoichiometric compositions of BNT derived materials tend to maintain stoichiometry by forming a secondary phase like TiO2 or by the evaporation of volatile compounds like Bi2O3 and Na2O. Due to this ability, variations of the Ti-content can be used to control the grain size of the material with little impact on electrical properties. The data also implies that the used processing temperatures lead to evaporation approximately 2 mol% of A-site cations during preparation since the sample with 1 mol% Ti-deficiency still shows TiO2 secondary phase.