Low temperature synthesis of pure SrSnO3 and the (BaxSr1−x)SnO3 solid solution by the polymerized complex method

Pure SrSnO3 and (Ba1−xSrx)SnO3 with compositions (x=0, 0.25, 0.5, 0.75 and 1) were directly prepared by the polymerized complex (PC) technique based on a modified Pechini-type reaction route at the relatively low temperature of 600°C. Anhydrous citric acid (CA) was added to SnCl4.xH2O dissolved in ethylene glycol (EG). After complete dissolution, BaCO3 and SrCO3 powders were added according to the desired mole ratio of the solid solution, and the mixture was stirred at 80°C for several hours until the solution became transparent. This solution, with a molar ratio (Ba+Sr)/Sn/CA/EG=1/1/10/40, was heated at 130°C to produce a yellowish transparent resin without any precipitation. The pyrolysis of the resin at 350°C yielded a powder precursor for (Ba,Sr)SnO3. Pure SrSnO3 is found with a pseudo cubic structure, which has some deviation from the perfect cubic lattice. X-ray diffraction (XRD) indicated the formation of pseudo-cubic (Ba,Sr)SnO3 when the barium, strontium–tin precursor was heat treated in air at 600°C or above for 2 h. The solid solution of (Ba,Sr)SnO3 exhibited a transition from the ideal cubic structure to a pseudo cubic structure.