Crystal structure refinement of ReSi1.75 with an ordered arrangement of silicon vacancies
Crystal structure refinement of ReSi1.75 with an ordered arrangement of silicon vacancies
复制标题
DOI：
10.1080/14786435.2011.570278
复制
发表时间：
2011-01-01
影响因子：
1.6
通讯作者：
Inui, Haruyuki
中科院分区：
文献类型：
--
作者：
Harada, Shunta;Hoshikawa, Hiroaki;Inui, Haruyuki
采用同步辐射X射线衍射和扫描电子显微镜相结合的方法研究了ReSi1.75的晶体结构和微观结构。ReSi1.75是MoSi2型四方C11(B)晶格中硅空位的有序排列，晶体结构为单斜晶系，空间群为Cm。Si原子在空位附近的原子位置明显偏离母体C11(B)结构中的相应位置，表现出反常的局部热振动，并伴随着较大的原子位移参数。有四个取向不同的磁区，其中两个通过围绕底层C11(B)晶格的c轴旋转90度而相互关联，另外两个是它们各自的孪晶。实验观测到的磁区边界的惯性面与铁弹性理论所预测的一致。
The crystal structure and microstructure of ReSi1.75 were investigated by synchrotron X-ray diffraction combined with scanning transmission electron microscopy. ReSi1.75 contains an ordered arrangement of vacancies in Si sites in the underlying tetragonal C11(b) lattice of the MoSi2-type and the crystal structure is monoclinic with the space group Cm. Atomic positions of Si atoms near vacancies are considerably displaced from the corresponding positions in the parent C11(b) structure, and they exhibit anomalously large local thermal vibration accompanied by large values of atomic displacement parameter. There are four differently-oriented domains with two of them being related to each other by the 90 degrees rotation about the c-axis of the underlying C11(b) lattice and the other two being their respective twins. The habit planes for domain boundaries observed experimentally are consistent with those predicted with ferroelastic theory.