Md Asif Shahriar, Md Mahfuzul Haque, Md. Mostafizur Rahman Suruj, Md Tauhidur Rahman
Strontium-doped barium titanate (Ba₁₋ₓSrₓTiO₃, BST) ceramics with Sr concentrations of 1%, 3%, and 5% were successfully synthesized using the conventional solid-state reaction method. High-purity barium carbonate (BaCO₃), strontium carbonate (SrCO₃), and titanium dioxide (TiO₂) powders were thoroughly mixed and milled for 24 hours, followed by pellet formation and sintering at 1150–1250 °C for 2 hours. The phase composition, microstructure, and dielectric properties of the samples were systematically investigated. X-ray diffraction (XRD) confirmed the formation of a single-phase perovskite structure, with a tetragonal-to-cubic phase transition observed as Sr content increased. The lattice parameters decreased with Sr incorporation due to the smaller ionic radius of Sr²⁺ (1.16 Å) compared to Ba²⁺ (1.36 Å), confirming successful A-site substitution. The dielectric constant increased from pure BaTiO₃ to 3 mol% Sr, Add quantitative comparison of dielectric loss values and clarify the test frequency. The optimized 3 mol% Sr composition exhibited enhanced crystallinity, high relative density, and low dielectric loss, indicating superior dielectric performance. These findings demonstrate that controlled Sr²⁺ substitution effectively tailors the structural and dielectric properties of BaTiO₃, making Ba₀.₉₇Sr₀.₀₃TiO₃ a promising lead-free dielectric material for advanced capacitor and transducer applications.