Department of Metallurgical & Materials Engineering, The University of Alabama, 301 7th Avenue, 116 Houser Hall, Tuscaloosa, AL 35487-0202 USA.
Microsc Microanal. 2011 Jun;17(3):398-402. doi: 10.1017/S1431927611000134. Epub 2011 Apr 15.
A series of multislice simulations to quantify the effect of various degrees of order, composition, and thickness on the electron diffracted intensities were performed using the L1₀ FePt system as the case study. The dynamical diffraction studies were done in both a convergent electron beam diffraction and selected area electron diffraction condition. The L1₀ symmetry demonstrated some peculiar challenges in the simulation, in particular between the {111} plane normal and the <111> direction, which are not equivalent because of tetragonality. A hybrid weighting function atom of Fe-Pt was constructed to account for S < 1 or nonequiatomic compositions. This statistical approach reduced the complexity of constructing a crystal with the probability that a particular atom was at a particular lattice site for a given order parameter and composition. Considerations of accelerating voltage, convergent angle, and thermal effects are discussed. The simulations revealed significant differences in intensity ratios between films of various compositions but equivalent unit cell numbers and degree of order.
采用 L1₀ FePt 体系作为实例，进行了一系列多层模拟，以量化不同程度的有序度、成分和厚度对电子衍射强度的影响。在会聚电子束衍射和选区电子衍射条件下进行了动力学衍射研究。L1₀ 对称性在模拟中表现出一些特殊的挑战，特别是在{111}面法线和<111>方向之间，由于四方性，它们并不等价。构建了一个 Fe-Pt 混合加权函数原子，以考虑 S < 1 或非等原子成分。这种统计方法降低了为给定有序参数和成分构建具有特定原子位于特定晶格位置的概率的晶体的复杂性。讨论了加速电压、会聚角和热效应的考虑因素。模拟结果表明，具有不同成分但等效晶胞数和有序度的薄膜之间的强度比存在显著差异。
