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

Abstract

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 raditional modeling of a single scattering energy, even for cases in which high scattering contrast naturally exists. Specifically, the material-specific structure of monodispersed Fe3O4/gamma-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/gamma -Mn2O3 core/shell nanoparticles with a diameter of 8.2 ( 0.2) nm consist of a core with a composition near Fe3O4 surrounded by a (MnxFe1_x)3O4 shell with a graded composition, ranging from x~0.40 at the inner shell toward x~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.Fil: Krycka, Kathryn L. . National Institute of Standards and Technology, Center for Neutron Research. Center for Neutron Research; Estados UnidosFil: Borchers, Julie A. . National Institute of Standards and Technology, Center for Neutron Research. Center for Neutron Research; Estados UnidosFil: Salazar Alvarez, German . Stockholms Universitet; SueciaFil: López Ortega, Alberto . Universitat Autonoma de Barcelona; España. Consejo Superior de Investigaciones Cientificas; España. Centro de Investigacion En Nanociencia y Nanotecnologia (cin2); EspañaFil: Estrader, Marta . Universitat Autonoma de Barcelona; España. Stockholms Universitet; Suecia. Centro de Investigacion En Nanociencia y Nanotecnologia (cin2); España. Consejo Superior de Investigaciones Cientificas; EspañaFil: Estradé, Sònia . Universidad de Barcelona; EspañaFil: Winkler, Elin Lilian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); ArgentinaFil: Zysler, Roberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); ArgentinaFil: Sort, Jordi . Universitat Autonoma de Barcelona; España. Institució Catalana de Recerca i Estudis Avancats; EspañaFil: Peiró, Francesca . Universidad de Barcelona; EspañaFil: Dolors Baró, Maria . Universitat Autonoma de Barcelona; EspañaFil: Kao, Chi-Chang . Stanford Synchrotron Radiation Lightsource; Estados UnidosFil: Nogués, Josep . Centro de Investigacion En Nanociencia y Nanotecnologia (cin2); España. Universitat Autonoma de Barcelona; España. Institució Catalana de Recerca i Estudis Avancats; Españ