Resolving Material-Specific Structures within Fe3O4|纬-Mn2O3 Core|Shell Nanoparticles Using Anomalous Small-Angle X-ray Scattering

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• 作者：Kathryn L. Krycka ; Julie A. Borchers ; German Salazar-Alvarez ; Alberto L贸pez-Ortega ; Marta Estrader ; S貌nia Estrad茅 ; Elin Winkler ; Roberto Daniel Zysler ; Jordi Sort ; Francesca Peir贸 ; Maria Dolors Bar贸 ; Chi-Chang Kao ; Josep Nogu茅s
• 刊名：ACS Nano
• 出版年：2013
• 出版时间：February 26, 2013
• 年：2013
• 卷：7
• 期：2
• 页码：921-931
• 全文大小：677K
• 年卷期：v.7,no.2(February 26, 2013)
• ISSN：1936-086X

文摘

Here it is demonstrated that multiple-energy, anomalous small-angle X-ray scattering (ASAXS) provides significant enhancement in sensitivity to internal material boundaries of layered nanoparticles compared with the traditional modeling of a single scattering energy, even for cases in which high scattering contrast naturally exists. Specifically, the material-specific structure of monodispersed Fe₃O₄|纬-Mn₂O₃ core|shell nanoparticles is determined, and the contribution of each component to the total scattering profile is identified with unprecedented clarity. We show that Fe₃O₄|纬-Mn₂O₃ core|shell nanoparticles with a diameter of 8.2 卤 0.2 nm consist of a core with a composition near Fe₃O₄ surrounded by a (Mn_xFe_1鈥?i>x)₃O₄ shell with a graded composition, ranging from x 鈮?0.40 at the inner shell toward x 鈮?0.46 at the surface. Evaluation of the scattering contribution arising from the interference between material-specific layers additionally reveals the presence of Fe₃O₄ cores without a coating shell. Finally, it is found that the material-specific scattering profile shapes and chemical compositions extracted by this method are independent of the original input chemical compositions used in the analysis, revealing multiple-energy ASAXS as a powerful tool for determining internal nanostructured morphology even if the exact composition of the individual layers is not known a priori.

Keywords:

core|shell nanoparticles; Fe₃O₄; 纬-Mn₂O₃; neutron scattering; anomalous X-ray scattering; SAXS