Sol-gel preparation and characterization of non-substituted and Sr-substituted gadolinium cobaltates

An aqueous sol-gel chemistry approach for the preparation of Sr-substituted perovskite gadolinium cobaltates Gd1−xSrxCoO3−δ (x = 0.0, 0.25, 0.5 and 0.75) has been applied. The metal ions, generated by dissolving starting materials in diluted acetic acid were complexed by EDTA to obtain the precursors for non-substituted and Sr-substituted GdCoO3. However, only two single-phase cobaltate samples with x = 0.0 and 0.25 have been obtained by the suggested sol-gel method. The influences of synthesis temperature and the amount of substituent on the phase purity of Gd1−xSrxCoO3−δ were investigated. The evolution of the gels during heating, composition and micro-structural features in the polycrystalline samples was studied by thermal analysis (TG/DSC), infrared spectroscopy (IR), powder X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM).