Influence of strontium doping on structural and dielectric properties of SmCrO₃

We have investigated the effect of Sr doping on the structural, morphological and dielectric properties of polycrystalline SmCrO₃ synthesized via sol-gel method. All the samples have been fitted with Rietveld refinement with a perovskite orthorhombic structure with Pnma space group confirming the single-phase nature. The grain sizes of prepared samples increase slightly from 350 nm ($x = 0$) to 375 nm ($x = 0.05$) and then decrease to 225 nm ($x = 0.1$). From the temperature- and frequency-dependent dielectric properties, it has been observed that Sr doping significantly enhances the dielectric constant and lowers the dielectric loss. Two debye-type relaxation processes are observed around low temperatures (below 100 K) and high temperature (above 200K) regions. However, the low-temperature region shifts towards lower temperature with doping and the peak broadens in the high-temperature region with an increase in Sr doping. The lower temperature showed thermally activated dielectric relaxations with activation energies of 0.08 and 0.07 eV and the activation energy for the higher temperature region is about 0.19 and 0.21 eV for Sm0.95Sr0.05CrO₃ and Sm0.9Sr0.1CrO₃, respectively. An equivalent circuit model is used to distinguish the intrinsic contributions of grains and grain boundaries.