NaM(WO_4)_2(M:Bi^(3+), Y^(3+), Gd^(3+))晶体生长与结构(英文)

CRYSTAL GROWTH AND STRUCTURE OF NaM(WO_4)_2 (M:Bi^(3+),Y^(3+),Gd^(3+))

采用提拉法生长出了钨酸铋钠[NaBi(WO4)2,NBW]、钨酸钇钠[NaY(WO4)2,NYW]和钨酸钆钠[NaGd(WO4)2,NGW]晶体。通过热重–差热分析(thermogravimetry–differential thermal analysis,TG–DTA),X射线衍射(X-ray diffraction,XRD)分析对晶体进行表征。由TG–DTA曲线得到NBW,NYW和NGW晶体的熔点分别为937.7,1210.0℃和1252.8℃。XRD分析表明:3种晶体都属于四方晶系、白钨矿结构、I41/a空间群。计算了3种晶体的晶胞参数,NBW晶体的晶胞参数要大于NYW和NGW晶体的。测试了晶体的红外光谱及Raman光谱,分析了晶体的振动模式,并将晶体振动光谱进行归属。通过比较认为三者结构基本相同。

NaBi（WO4）2 （NBW）, NaY（WO4）2 （NYW） and NaGd（WO4）2 （NGW） single crystals were grown by the Czochralski method. These crystals were characterized by thermogravimetry-lifferential thermal analysis （TG-DTA） and X-ray diffraction （XRD） The TG-DTA curves indicate that the melting points of the NBW, NYW and NGW crystals are 937.7, 1 210.0 and 1 252.8 ℃, respectively. The XRD analyses show that these crystals all belong to a tetragonal system, with a scheelite-type structure and space group I 41/a. The lattice parameters of NBW crystal are larger than those of NYW and NGW crystals. The infrared （IR） spectra and Raman spectra of these crystals were measured, and the vibration frequencies of the IR and Raman active modes for these crystals were assigned. Comparison of the IR spectra and Raman spectra of these crystals reveals that the structures of NBW, NYW and NGW crystals are basically identical.