Schnedlitz Martin, Knez Daniel, Lasserus Maximilian, Hofer Ferdinand, Fernández-Perea Ricardo, Hauser Andreas W, Pilar de Lara-Castells María, Ernst Wolfgang E
Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy, Graz University of Technology, Steyrergasse 17, A-8010 Graz, Austria.
J Phys Chem C Nanomater Interfaces. 2020 Jul 30;124(30):16680-16688. doi: 10.1021/acs.jpcc.0c04561. Epub 2020 Jul 9.
The temperature-induced structural changes of Fe-, Co-, and Ni-Au core-shell nanoparticles with diameters around 5 nm are studied via atomically resolved transmission electron microscopy. We observe structural transitions from local toward global energy minima induced by elevated temperatures. The experimental observations are accompanied by a computational modeling of all core-shell particles with either centralized or decentralized core positions. The embedded atom model is employed and further supported by density functional theory calculations. We provide a detailed comparison of vacancy formation energies obtained for all materials involved in order to explain the variations in the restructuring processes which we observe in temperature-programmed TEM studies of the particles.
通过原子分辨透射电子显微镜研究了直径约5纳米的铁、钴和镍金核壳纳米颗粒的温度诱导结构变化。我们观察到温度升高导致从局部能量最小值向全局能量最小值的结构转变。实验观察结果伴随着对所有核壳颗粒的计算建模，这些颗粒的核位置要么是集中的，要么是分散的。采用了嵌入原子模型，并得到密度泛函理论计算的进一步支持。我们对所有相关材料的空位形成能进行了详细比较，以解释在颗粒的程序升温透射电子显微镜研究中观察到的重组过程的变化。
