[Synthesis and spectral properties of Eu3+-doped MCeO3(M==Sr, Ba)].

Eu3+ -doped MCeO3 (M==Sr, Ba) powder samples were prepared by a solid-state method, and their characteristics were investigated by the use of XRD an d fluorescence spectra. The XRD results show that Eu3+ ions hav e a preferencefor M2+ over Ce4+ sites in MCeO3 (M==Sr, Ba) lattice. The excitation spectra of SrCeO3:Eu3+ and BaCeO3:Eu3+ display a much broad absorption band peaking at about 311 nm and 320 nm, respectively.

[Synthesis and spectral properties of a new europium strontium oxide SrEu2O4].

A new europium strontium oxide was synthesized by high-temperature solid state reaction of SrCO3 with Eu2O3 in air. The new multiple oxide was characterized by use of XRD, TG/DTA and fluorescence spectra. The XRD results show that the molecular formula of the europium strontium oxide is SrEu2O4, whose structure is isostructural with that of BaEu2O4 reported earlier.

[Formation mechanism of Sr2CeO4 and its effect on spectral properties].

The phase composition of SrCO3 and CeO2 (2:1) powder mixture calcined at different temperatures was identified by X-ray diffraction method. It was found that there were two types of formation mechanism of Sr2CeO4. When the starting powder mixture was fired above 1000 degrees C, the unstable intermediate phase SrCeO3 developed, which then reacted with SrCO3 to form the final product Sr2CeO4, however when the sintering temperature was lower, SrCO3 and CeO2 were converted directly to Sr2CeO4.