MASOUD KHOSRAVI - Department of nano and advanced materials, Material and Energy research Center, Meshkindasht, Karaj, hran
MOHHAMAD ALI BAHREVAR - Department of semiconductor materials and Energy Research Center, Meshkindasht, Karaj, Iran
KAMRAN AHMADI - Department of semiconductor materials and Energy Research Center, Meshkindasht, Karaj, Iran

ABO type of perovskite compounds, such as BaTiO, SrTiO, and solid solution of them viz., Ba-Sr, TiO, (BST), are very important candidates for a wide range of device applications. Various innovative approaches,like sol-gel spray pyrolysis, combustion synthesis, chemical coprecipitation, hydrothermal method, etc. have been used to synthesize BST powders. The performance parameters in these devices are highly dependent on the physical and chemical characteristics, namely, stoichiometry, homogeneity, powders size and its distribution, phase purity, etc. of starting BST powders.Nano crystalline and well dispersed barium strontium titanate (BST) powders were prepared by citrate precursor method. this method possessing many advantages, such as a relatively low calcination temperature, short duration and exact stoichiometric ratio. This method involved direct crystallization of a white precursor from a stable solution in the citric acid-ethylene glycol-titanium isopropoxide (TTIP)-M (M=Ba, Sr) system under a specific pH value range. Many desirable features can be brought in when certain ferroelectric materials as BSTare doped with calculated amount of foreign atoms.The ultraviolet-visible spectra of the pure barium strontium titanate (Bao SroaTiO3) and the Gd-doped Bai. Sr.TiO3 were measured. The crystalline phase and morphology of the resulted powders were investigated by XRD and SEM. The pure barium strontium titanate exhibited an ultraviolet (UV) absorption effect. It was found that The addition of Gd in ABO, perovskite, effects on BST absorption spectrum.

barium strontium titanate, nano powder, Gd doping, optical properties