Impact of the synthesis method on the structural, microstructural, and electrical properties of ce-doped SrTiO3 perovskite

Official URL: https://dx.doi.org/10.1134/S0036024426700196

This study aims to investigate the effect of synthesis methods on the properties of SrCexTiO3 (x = 0.05, 0.1) prepared through solid-state and sol–gel routes in air. X-ray diffraction (XRD) indicates that solid-state synthesis yields a single perovskite phase at x = 0.05 composition. While at x = 0.1, a minor CeO2 phase has appeared with perovskite, and the same occurs for the two compositions synthesized via the sol–gel method. Electrical conductivity results determined by electrical impedance spectroscopy demonstrated that solid-prepared samples exhibit higher conductivity as the Ce content increases, with a 1.6 times increase from x = 0.05 to 0.1. In contrast, the sol–gel method resulted in a more substantial increase in conductivity, 11 times higher, from x = 0.05 to 0.1. However, the conductivity of the sol–gel samples remains lower than that of the solid-state samples, despite the smaller crystallite size achieved in the sol–gel method. Activation energy (Ea) values also supported these observations, revealing that cerium doping introduces structural defects, reduces Ea, and facilitates electrical conductivity. The samples prepared by the solid route presented a lower Ea (from 0.79 to 0.66 eV when x changes from 0.05 to 0.1) than in the sol–gel samples (where Ea varies from 0.83 to 0.80 eV when x changes from 0.05 to 0.1).