运用数字暗场和结构重构方法测定FePt纳米粒子的正二十面体结构(英文)

Icosahedra structure determination of FePt nanoparticle by means of digital dark field and structure reconstruction method

小粒子结构一直是人们关注的研究热点,上世纪70年代运用暗场像技术发现了具有多重孪晶结构的正二十面体和正十面体结构。近年来,人们已经能够合成直径只有几纳米、结构复杂的纳米粒子,传统的高分辨像和衍射等方法难以获得这些纳米粒子的结构。本文以直径约6nm的FePt粒子为研究对象,通过系列欠焦像波函数重构获得了该粒子亚埃分辨率高分辨相位像,并对该相位像进行了数字暗场像分析研究,通过结构重构并结合高分辨像模拟测定该粒子具有二十面体结构,为确定具有复杂结构的纳米粒子结构提供了一种新途径。

FePt nanoparticles with about 6 nm in diameter have been fabricated by an inert-gas condensation method with in-flight annealing. High-resolution transmission electron microscopy （HRTEM） phase images with sub-Angstrom resolution of these FePt nanoparticles have been obtained with focal series reconstruction. Digital dark field method combined with structure reconstruction as well as HRTEM simulations reveal that these nanoparticles have an icosahedra structure.