Sol-gel synthesis and characterization of Na0.5K0.5NbO3 thin films

Thin films of the perovskite structured Na0.5K0.5NbO3 (NKN) have been synthesized with three different sol-gel methods, viz. the alkoxide method, a modified Pechini method and a somewhat novel oxalate method, based on 2-methoxy ethanol as solvent with oxalic acid and ethylene glycol as chelating ligand and stabilizer. Only one method (the modified Pechini method) gave pure NKN phase while the other two methods gave extra peaks in the X-ray diffraction patterns, indicating that other, unidentified, phases were present. SEM images revealed grain sizes ranging from 100 to 300 nm.