Structural properties and impedance spectroscopy of solid-state synthesized Sr2MnTiO6 perovskite ceramics for oxide electronic applications

Sr 2 MnTiO 6 (SMT) double-perovskite ceramics were synthesized by a conventional solid-state reaction route and investigated in terms of their structural, microstructural, and temperature-dependent electrical properties. X-ray diffraction analysis combined with Rietveld refinement indicates that the major phase is described by a tetragonal I4/m structure, accompanied by a minor secondary phase. The refined lattice parameters are a = b = 5.5147(5) Å and c = 7.8091(6) Å, with a unit-cell volume of 237.49(3) Å 3 . SEM observations reveal a relatively dense microstructure with well-developed grains and limited intergranular porosity. Temperature-dependent impedance spectroscopy performed from 290 to 550 K shows a systematic shift of the Z″ relaxation response toward higher frequencies with increasing temperature, indicating thermally activated relaxation. The impedance response is associated with non-ideal relaxation behavior and contributions from electrically distinct regions of the ceramic. Arrhenius analysis of the relaxation time gives an activation energy of approximately 0.312 eV. The results indicate that the electrical response of SMT ceramics is strongly temperature-dependent and governed by thermally activated charge transport and relaxation processes. These findings provide a basis for further investigation of SMT as a functional oxide ceramic for temperature-dependent electronic and dielectric applications.