Investigating the Morphological Evolution, Electron Paramagnetic Resonance, & Electrical Properties of Barium Titanate with Sn-Incorporation

The present work investigates the effects of increasing tin substitution for titanium in barium titanate (BT), with a primary focus on the influence of doping on grain growth, defect concentration, electrical properties, and diffusivity. The study involves the preparation of various tin-doped compositions (BaTi_1-zSn_zO₃; z = 0–0.1) using the solid-state synthesis technique. XRD (X-ray diffraction) technique was used to determine the purity of the phase of these samples. Scanning electron micrographs revealed an increase in grain size up to 5 mol% tin doping, but the 7 mol% tin-doped sample showed large agglomerates formed by the inter-diffusion of smaller particles. Electron Paramagnetic Resonance (EPR) results indicated the presence of vacancy defects and Mn²⁺ impurity ions in the material. The dielectric properties of these samples were also examined, and the impact of tin incorporation on the diffusivity of BT was noted. The composition with 2 mol% of tin showed the highest value of dielectric constant (5533 at T_c) and remnant polarization (2P_r = 11.56 µC/cm²). The saturation at a lower applied field of the tin doped samples in comparison to the undoped BT was also observed.