Morphology characterization and dielectric performances of Ce-doped barium strontium titanate powders prepared by modified citrate method

Abstract

ABSTRACTCitrate acid (CA), ethylene glycol (EG), and absolute ethyl alcohol (AEA) were combined to synthesize 0∼5% mol cerium doped barium strontium titanate (Ce-BST) powders, and the morphology characterization and dielectric performances of the powders were studied. X-ray diffraction (XRD) shows that the powders have ABO3 perovskite structures with no secondary phase until ≥4% mol because AEA avoids the formation of cerium hydroxide caused by the hydrolyzation of Ce3+ ions, and Ce3+ ions enter into lattices to make lattice parameters increase. Scanning electronic microscope (SEM) reveals that Ce3+ ions affect grain growth and refine grain size with uniform grain size of about 100 nm at 2 mol%. Permittivity and loss tangent of the doped powders are decreased, where 2 mol% corresponds to the optimum dielectric properties with permittivity of 58 and loss of 0.007 at 1 GHz, which can meet the requirements in many applications like microwave devices. The relation between dielectric properties and Ce doping is also discussed.