Temperature dependent structural phase transition and relaxation in Lithium Cobalt Antimonate

Abstract This work reports an understanding of the effect of thermal processing on the structural stability and dielectric response of Lithium Cobalt Antimonate (Li₃Co₂SbO₆). We aim to analyze, hitherto unexplored dielectric and electrical transport properties of Li₃Co₂SbO₆ after sintering for the first time. The sintering-induced structural phase transition and dielectric relaxation in Li₃Co₂SbO₆ has been analyzed and explained. X-ray diffraction analysis revealed sintering-induced structural phase transformation (order-disorder) from the unsintered monoclinic phase (space group C2/m) to the orthorhombic phase (space group Fddd) on sintering at 1200°C. This observation is corroborated by Raman spectroscopy results indicated by the absence of the characteristic soft mode in the sintered orthorhombic Li₃Co₂SbO₆ phase. Microstructural analysis confirmed the polycrystalline nature of the samples, accompanied by grain growth on sintering. The non-Debye nature of the dielectric relaxation was confirmed by relaxation peak fitting using the Havriliak–Negami (HN) function. Electrical equivalent-circuit modeling of the complex Impedance spectra suggested the presence of grain, grain-boundary, and electrode-polarization. effects. Conductivity analysis, fitted using Jonscher’s power law, suggested a combination of correlated barrier hopping (CBH) and quantum mechanical tunneling (QMT) mechanisms. A Systematic structure-property correlation is evidenced and explained