Dielectric properties and substitution mechanism of samarium-doped Ba0.68Sr0.32TiO3 ceramics

Abstract Ba 0.68 Sr 0.32 TiO 3 ceramics of perovskite structure are prepared by solid state reaction method with addition of x mol% Sm 2 O 3 , and their dielectric properties are investigated. It is found that, integrating with the lattice parameters and tolerance factor t , there is an alternation of substitution preference of Sm 3+ for the host cations in perovskite lattice. Owing to the replacement of Sm 3+ ions for Ba 2+ ions in the A site, T c rises with the increase of Sm 2 O 3 doping when the doping content is below 0.1 mol%; meanwhile, when the content is more than 0.1 mol%, Sm 3+ ions tend to occupy the B-site, causing a drop of T c . Owing to the modifications of Sm 3+ doping, dielectric constant, dissipation factor and temperature stability of dissipation factor are influenced remarkably, making it a superior candidate for environment-friendly applications. Moreover, the creation of oxygen vacancies controls the dielectric constant when the addition is above 0.1 mol%, so the dielectric constant decreases with increasing of samarium.