Polaronic charge transfer characteristics and impedance properties of SrSn_1-xCo_xO₃ ceramics

In this study, single-phase polycrystalline SrSn_1-xCo_xO₃ (x = 0–0.9) ceramics were prepared using a conventional solid-state reaction method. The substitution of Sn ions at B-site by Co ions did not affect the crystal structure of these ceramics significantly. The dielectric performance of the fabricated SrSn_1-xCo_xO₃ samples was investigated through dielectric constant, complex impedance, and electric modulus measurements. The frequency- and temperature-dependent dielectric measurements suggest that the dielectric properties exhibit a positive correlation with temperature, while a negative correlation with frequency. A colossal permittivity with a lower dielectric loss was obtained in the x = 0.3 sample. Both Maxwell–Wagner polarization and dipole polarization were observed, contributing to the significant increase in the dielectric constant and relaxation phenomena. The dielectric properties and relaxation mechanism are thought to be ascribed to the existence of space charge, defect complexes, and the intricate microstructure.