Solid state synthesis of lead-free Sm-doped Na_0.5Bi_4.5Ti₄O₁₅ ceramics for enhanced dielectric and electrical properties

Here we report the synthesis of Sm-doped Na_0.5Bi_4.5Ti₄O₁₅ (Na_0.5Sm_0.5Bi₄Ti₄O₁₅) lead-free ceramics via a conventional solid-state technique. Investigations of Na_0.5Bi_4.5Ti₄O₁₅ (NBT) and Na_0.5Sm_0.5Bi_4.5Ti₄O₁₅ (NSBT) ceramics were demonstrated in detail to understand the composition-based structure-property of Aurivillius compounds and related functional material. Dielectric properties for frequency and temperature in a wide range were analyzed. The conduction activation energy values of NSBT ceramics are obtained to be 1.40 eV, whereas, the NBT ceramics get the value to be 1.31 eV. At higher temperatures, the conduction activation energy value of NSBT ceramics is 1.32 eV for both frequencies of 100 Hz and 1 kHz, whereas, for NBT compounds, the calculated value is 1.27 eV for both frequencies. The simulation performed on the impedance data for capacitive and resistance elements shows well-fitting curves which indicates a single relaxation behavior in the material. Similarly, the AC-conductivity data were analyzed which gives different conduction processes and relaxation activation energies in the NSBT ceramics.