STRUCTURAL REFINEMENT OF SUPERLATTICES FROM X-RAY-DIFFRACTION
STRUCTURAL REFINEMENT OF SUPERLATTICES FROM X-RAY-DIFFRACTION
复制标题
DOI：
10.1103/physrevb.45.9292
复制
发表时间：
1992-04-15
影响因子：
3.7
通讯作者：
BRUYNSERAEDE, Y
中科院分区：
文献类型：
--
作者：
FULLERTON, EE;SCHULLER, IK;BRUYNSERAEDE, Y
我们提出了一个一般的程序，用于定量结构细化的超晶格结构。为了分析各种超晶格，我们导出了一个通用的运动学衍射公式，其中包括随机，连续和离散的波动，从平均结构。我们表明，只有一个单层的每种材料的结构因子必须平均的随机变量，并证明这种关系是等价的早期，不太一般的模型。实施非线性拟合算法来拟合整个X射线衍射曲线，获得描述平均超晶格结构和偏离该平均值的精细参数。我们比较结构细化的结果，从其他测量独立获得的结果。在Mo/Ni和Nb/Cu超晶格生长过程中引入的人工粗糙度精确地再现了细化。从这个细化过程中获得的Ag/Mn的晶格参数是在非常好的协议从独立的扩展X射线吸收精细结构和X射线光电子衍射研究获得的值。可以精确地确定层的相对厚度，如对于Cu/Ni与化学分析相比、对于W/Ni与校准溅射速率相比以及对于Mo/Ni与低角度分布相比所证明的。
We present a general procedure for quantitative structural refinement of superlattice structures. To analyze a wide range of superlattices, we derived a general kinematical diffraction formula that includes random, continuous, and discrete fluctuations from the average structure. We show that only the structure factor of one single layer of each material has to be averaged over the random variables and prove that this relation is equivalent to earlier, less general models. Implementing a nonlinear-fitting algorithm to fit the entire x-ray-diffraction profile, refined parameters that describe the average superlattice structure and deviations from this average are obtained. We compare the results of structural refinement to results obtained independently from other measurements. The roughness introduced artificially during growth in Mo/Ni and Nb/Cu superlattices is accurately reproduced by the refinement. The lattice parameters of Ag/Mn obtained from this refinement procedure are in very good agreement with the values obtained from independent extended x-ray-absorption fine-structure and x-ray photoelectron diffraction studies. The relative thicknesses of the layers can be accurately determined, as proved for Cu/Ni in comparison with chemical analysis, for W/Ni compared to the calibrated sputtering rate, and for Mo/Ni compared to the low-angle profile.