X-Ray and neutron diffraction studies of atomic scale structures of crystalline and amorphous TbFe2Dx
X-Ray and neutron diffraction studies of atomic scale structures of crystalline and amorphous TbFe2Dx
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DOI：
10.1016/s0925-8388(02)00842-3
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发表时间：
2003-01
影响因子：
6.2
通讯作者：
K. Itoh;Kazuyuki Kanda;K. Aoki;T. Fukunaga
中科院分区：
文献类型：
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作者：
K. Itoh;Kazuyuki Kanda;K. Aoki;T. Fukunaga
采用X射线衍射和中子衍射技术研究了由C15 Laves相化合物TbFe_2吸收氘气制备的（c-）TbFe_2D_（3.8）和（a-）TbFe_2D_x（x=3.0，2.0）的短程结构。原子间距离和配位数由径向分布函数RDF（r）s导出。X射线衍射的RDF（r）s表明，c-TbFe 2D 3. 8为菱面体结构，但与C15 Laves相的c-TbFe 2D 3.8相比，金属原子的排列略有不同。与此相反，我们的研究结果表明，有一个很大的差异，在c-TbFe_2和a-TbFe_2Dx（x=3.0，2.0）之间的金属原子的排列和a-TbFe_2Dx（x=3.0，2.0）中存在的Fe和Tb原子的集群。中子衍射的RDF（r）s表明，在c-TbFe_2D_（3.8）中D原子占据2 Tb +2Fe的四面体位置，而在a-TbFe_2Dx（x=3.0，2.0）中D原子占据4 Tb，3 Tb +1Fe和2 Tb +2Fe的四面体位置。
Both X-ray and neutron diffraction techniques were employed in order to elucidate short-range structures of crystalline (c-)TbFe2D3.8and amorphous (a-)TbFe2Dx(x=3.0, 2.0) prepared by deuterium absorption of the C15 Laves phase compound TbFe2. Interatomic distances and coordination numbers were derived from the radial distribution functions, RDF(r)s. The RDF(r)s observed by X-ray diffraction indicated that c-TbFe2D3.8adopts a rhombohedral structure, but there is a little difference in the arrangement of metal atoms between the original C15 Laves phase c-TbFe2and the rhombohedral c-TbFe2D3.8. In contrast, our results indicated that there is a large difference in the arrangement of metal atoms between c-TbFe2and a-TbFe2Dx(x=3.0, 2.0) and there are clusters of Fe and Tb atoms in a-TbFe2Dx(x=3.0, 2.0). RDF(r)s observed by the neutron diffraction indicated that the D atoms occupy tetrahedral sites consisting of 2Tb+2Fe in c-TbFe2D3.8, while they occupy sites consisting of 4Tb, 3Tb+1Fe and 2Tb+2Fe in a-TbFe2Dx(x=3.0, 2.0).