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The Determination the Phason in Cu-Ga-Zn Icosahedral Quasicrystal Phase using with the Huang Diffuse Scattering method

黄漫散射法测定Cu-Ga-Zn二十面体准晶相中的相子

基本信息

批准号：
15540306
负责人：
MORI Masahiro
金额：
$ 2.3万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540306/
关键词：
Quasicrystal Icosahedral phason x-ray diffraction electron diffraction diffuse scattering Zn X線回析電子線回析

项目摘要

The main aim of this research is to study the quasicrystal phase stability of Cu-Ga-Zn-Mg icosahedral phase. It have already been reported that a CuGaZnMg is an P-type icosahedral phase. But the other icosahedral phases are F-type icosahedral. We have made the program of the Huang scattering for icosaheral symmetry crystal. The experimental results o are in the icosahedral phases as follows.1)The pseudo-gap around the Fermi surface in the Cu-Ga-Zn-Mg icosahedral phase is observed by the UPS study and that in the Ga-Zn approximant is not observed. 2)The depth and width of the gap is 0.6 and 0.2eV, respectively. 3)It is very difficult for the x-ray study to be done. It seems that one of the reason is multi scattering effect is not ignored.The calculated results of the Huang scattering intensity are in the icosahedral phases as follows.1)The Huang diffuse distribution around the reflection along the 2-fold axis is elliptic spread toward the transverse direction. 2)The Huang diffuse distri … More bution around the reflection along the 5-fold and 3-fold axis is not elliptic spread toward the transverse direction and like the complex shape. 3)The diffuse scattering intensity distribution of Al-Pd-Mn is symmetrical along the longitudinal direction, but that of Al-Cu-Fe is asymmetric. The reason, called "asymmetrical" in this case, is that the center of the rhombus is notjust on the diffraction point, but is located on the slightly inside. 3)The shape of diffuse intensity contour depends on the intensity. 4)The intensity of the diffuse scattering in Al-Cu-Fe depends little on the temperature below 300K.Therefore, it is thought that the diffuse scattering is mainly produced by the defects. In the defects, a defect, called a (frozen) "phason" proper to a quasicrystal, is naturally included besides an impurity and/or defect included in a "usual" crystal. The experimental result seems to show the limit of elastic approximation as Huang scattering. The contour of the diffuse scattering intensity cannot individually be explained as every map of Huang scattering, and seems to consist of the sum of all three diffuse scattering components.As the comparison between experimental and calculation, we can think followings. The major defects in Al-Pd-Mn and Al-Cu-Fe can be exchange-type, which are created by interchange of atoms and/or atomic clusters. However, the concentration of atoms and atomic clusters is unchanged from the ideal structure by this type of defect. Random phason is clearly classified into this type. The type of the defect is similar to the exchange-type but is accompanied by deviation of concentration of atoms and atomic clusters from the ideal state. As the "asymmetrical" cannot be explained with the approximation of Huang scattering, it is probably caused by a size effect. Less

本研究的主要目的是研究Cu-Ga-Zn-Mg二十面体相的准晶相稳定性。已经报道CuGaZnMg是P型二十面体相。其他二十面体相均为F型二十面体相。编制了二十面体对称晶体黄散射的计算程序。在二十面体相中的实验结果如下：1）UPS研究发现Cu-Ga-Zn-Mg二十面体相费米面附近存在赝能隙，而Ga-Zn近似相费米面附近没有赝能隙。2)差距的深度和宽度分别为0.6和0.2eV。（3）X射线检查非常困难。计算结果表明，黄散射强度在二十面体相位中的分布为：1）黄散射强度沿沿着2重轴的分布为椭圆形，并向横向扩展. 2)黄泛分布 ...更多信息反射波沿着5重轴和3重轴周围的分布不是椭圆形，而是向横向扩展，呈复杂形状。3)Al-Pd-Mn的漫散射强度沿纵向沿着对称分布，而Al-Cu-Fe的漫散射强度沿纵向不对称分布。在这种情况下，其原因被称为“不对称”，因为菱形的中心不仅在衍射点上，而且位于稍微内侧。3)漫射强度轮廓的形状取决于强度。4)Al-Cu-Fe中的漫散射强度在300 K以下对温度的依赖性很小，因此认为漫散射主要是由缺陷引起的。在缺陷中，除了包括在“通常”晶体中的杂质和/或缺陷之外，还自然地包括被称为准晶固有的（冻结的）“相位子”的缺陷。实验结果似乎表明了弹性近似作为黄散射的极限。漫散射强度的等值线不能单独解释为黄散射的每一幅图，而似乎是由所有三个漫散射分量的总和组成。Al-Pd-Mn和Al-Cu-Fe中的主要缺陷可以是交换型的，其通过原子和/或原子团簇的交换而产生。然而，原子和原子团簇的浓度因这种类型的缺陷而与理想结构不变。随机相位子被明确地划分为这种类型。缺陷的类型类似于交换型，但伴随着原子和原子团簇的浓度偏离理想状态。由于黄散射近似不能解释这种“不对称”现象，因此它可能是由尺寸效应引起的。少