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

摘要

Citrate acid (CA), ethylene glycol (EG), and absolute ethyl alcohol (AEA) were combined to synthesize 0 approximate to 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 ABO(3) 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 100nm at 2mol%. Permittivity and loss tangent of the doped powders are decreased, where 2mol% corresponds to the optimum dielectric properties with permittivity of 58 and loss of 0.007 at 1GHz, which can meet the requirements in many applications like microwave devices. The relation between dielectric properties and Ce doping is also discussed.