Lu_2O_3纳米粉体和透明陶瓷中掺杂Nd^(3+)的局域结构研究

Local Structure of Nd^(3+) in Lu_2O_3 Nanopowders and Transparent Ceramics

利用扩展X射线吸收精细结构光谱(EXAFS)研究了不同掺杂浓度Nd3+∶Lu2O3纳米粉体和透明陶瓷中Nd3+的局域结构.结果表明,在不同条件下Nd3+均以固溶取代Lu3+的方式进入Lu2O3基质晶格,掺杂Nd3+原子的第一配位键长约为0.225 nm,小于Nd2O3纳米粉中Nd—O第一近邻键长0.251 nm,而大于Lu2O3中Lu—O第一近邻键长0.221 nm.在Lu2O3晶格中掺杂Nd离子的局域环境与基质晶体场、掺杂浓度以及材料聚集状态密切相关,随着Nd掺杂量从0.5%提高至3%,纳米粉体无序度由5.6×10-4nm2升高到8.5×10-4nm2,Nd3+∶Lu2O3纳米粉体中Nd3+的第一近邻Nd—O键长、配位数和无序度因子均比透明陶瓷的大.

Local structures of doped Nd3＋ in Lu2O3 nanopowders and transparent ceramic were investigated through X-ray absorption fine structure（EXAFS）.EXAFS spectroscopy of Nd L3 edge at about 6215 eV demonstrates that doped Nd atoms has entered Lu2O3 host lattice by substitution solid solution with trivalence state.The first shell Nd—O distances are around 0.225 nm for Nd3＋∶Lu2O3 samples.Fitting results of EXAFS present detailed information about species of Nd near-neighborhood coordination atoms,inter-atom distance,coordination number and disorder parameter.The Nd—O first shell distance in nanopowder increases 0.007 nm as Nd3＋ doping concentration raises from 0.5% to 3%,whereas the Nd—O first shell distance in transparent ceramics exhibites little change.Owing to a large amount of Nd3＋existence on particle surface,Nd3＋∶Lu2O3 nanopowders exhibites a lager first shell nearest Nd—O distance,coordination number and disorder parameters than those of transparent ceramics.