Structural and dielectric relaxor properties of Ba 1- x Mg x TiO 3 ceramics prepared through a hydrothermal route

Abstract

Polycrystalline samples of lead-free Ba_1-xMg _x TiO₃ (where x = 0.05, 0.10, 0.15) have been fabricated by a hydrothermal method. Single-phase perovskite-type X-ray diffraction patterns were observed and samples have a phase with a tetragonal structure at room temperature for all compositions. The SEM image of the powder shows the agglomeration with increment of Mg concentrations. Small grains with average grain sizes of ∼20 ± 5 nm are uniformly distributed over the mesocrystals. TEM specimens show well-dispersed spherical barium magnesium titanate nanoparticles and diameter of these particles is around 270–300 nm. A dielectric study of Ba_1-xMg _x TiO₃ ceramics as a function of temperature suggested that with increasing substitution concentration the dielectric constant decreased and the Curie temperature shifted towards the lower temperature side. The dielectric diffusivity (γ) was found to be maximum (1.86) for substitution of x = 0.10 in Ba_1-xMg _x TiO₃ compounds. The activation energy (Ea) was found to increases with increasing substitution concentration in BMT compounds.