Pitfalls in the synthesis of nanoscaled perovskite type compounds. Part II: Influence of different sol-gel preparation methods and characterization of nanoscaled mixed crystals of the type Ba1−xSrxTiO3 (0⩽x⩽1)

The preparation of mixed crystals Ba1−xSrxTiO3 (0⩽x⩽1) by an acetate based sol-gel method was monitored by TG/DTA, TG–MS and XRD with respect to the reaction paths and the quality of the products. Depending on x, there is a more or less pronounced segregation of the alkaline earth compound leading at first to by-products richer in Ba than the perovskite phase itself. Chemical homogeneity will only be restored after prolonged heating at high temperatures where the primary crystallites of the ABX3 compound will have left the nanoregime and new ones will be formed during the decomposition of the by-products giving a more bimodal size distribution. Due to such pitfalls the desired properties of the products and especially their physical characteristics important for use in electrical devices will not always be ensured.