Effect of oxygen treatment on structure and electrical properties of Mn-doped Ca0.6Sr0.4TiO3 ceramics

Different oxygen treatment methods, including O2 and N2 annealing, were conducted on Ca0.6Sr0.4TiO3 (CST) ceramics with varying Mn content (0 mol%, 0.5 mol% and 2.0 mol%). Structure characterization, including XRD and SEM, indicated the minimal effect of annealing on the microstructure. Grain boundaries were found to be sensitive to oxygen treatments, and annealing in O2 resulted in increased grain boundary resistance, while in N2 led to the opposite result. The insulating properties of bulk ceramics were found to be dominated by grain boundaries. Both the concentration and mobility of oxygen vacancies were confirmed to affect the energy storage properties to some extent in this work.