期刊
JOURNAL OF NON-CRYSTALLINE SOLIDS
卷 354, 期 18, 页码 1943-1947出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.jnoncrysol.2007.12.007
关键词
synchrotron radiation; X-ray diffraction; crystal structure; Ce3+; Tb3+; 4f-5d transitions; luminescence
The Mg-Sr-Ba hexagonal aluminates (MgSrBa)Al12O19 doped with either Ce3+ or Tb3+ ion have been synthesized by solid-state reaction. Crystal structure variations with the increasing Ba2+ concentration have been thoroughly studied. When the concentration of Ba2+ reaches 0.39, the crystal structure becomes the ideal magnetoplumbite-type (No. PDF #80-1195), however, it becomes the same structure as BaMgAl10O17 with space group P6(3)/mmc when Sr2+ is completely replaced by Ba2+ ions. In Ce3+ doped compounds, the emission peak of the Ce3+ ion is gradually red-shifted when the concentration of Mg2+ ion increases, while the 4f-5d transition of Ce3+ at 260 nm splits into five components. In the Tb3+ doped compounds, the spin-allowed and spin-forbidden 4f-5d transitions of Tb3+ have been observed. The intensity of the spin-forbidden 4f-5d transition is gradually increased with decreasing Sr2+ concentration and becomes dominant when Sr2+ is completely replaced by Ba2+. These experimental observations are also discussed in the context and match well with the theoretical calculations of 4-5d transitions of Tb3+. (c) 2008 Elsevier B.V. All rights reserved.
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