R_2Zr_2O_7と(R_1-xEu_x)_2Zr_2O_7の結晶構造と蛍光特性

概要

論文の詳細を見る
R_2Zr_2O_7 and (R_<1-x>Eu_x)_2Zr_2O_7 (R=La, Pr, Sm, Eu, Gd, Tb, Er, Y) were prepared at 1600℃ in air and their fluorescence properties were studied. The crystal structures of these compounds were pyrochlorite- type for the light rare earths and CaF_2- type for the heavy rare earths, respectively. However, Gd_2Zr_2O_7 and Y_2Zr_2O_7 showed broad and small (111) X-ray diffraction peaks which were characteristic of the pyrochlorite- type structure. Further, annealing at 1500℃ increased the intensity and the sharpness of the (111) peak of Gd_2Zr_2O_7. When the compounds were excited by the 254 nm line, only the Eu-doped La_2Zr_2O_7 Gd_2Zr_2O_7 and Y_2Zr_2O_7 showed emission spectra due to Eu^<3+> ions. These spectra and X- ray diffraction, showed that in La_2Zr_2O_7 almost all rare earth ions occupy D_<3d> symmetry sites, but in Y_2Zr_2O_7 and Gd_2Zr_2O_7 most rare earth ions occupy most of the O_h symmetry sites and partially the D_<3d> sites.
社団法人日本セラミックス協会の論文
1988-02-01