Thorium/uranium mixed oxide nanocrystals： Synthesis, structural characterization and magnetic properties

• Published in: Nano research Vol. 7; no. 1; pp. 119 - 131
• Main Authors: Hudry, Damien, Griveau, Jean-Christophe, Apostolidis, Christos, Walter, Olaf, Colineau, Eric, Rasmussen, Gert, Wang, Di, Chakravadhaluna, Venkata Sai Kiran, Courtois, Eglantine, Kübel, Christian, Meyer, Daniel
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2014; Springer Nature B.V
• Subjects: Actinides; Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Chemistry and Materials Science; Condensed Matter Physics; Magnetic properties; Materials Science; Mixed oxides; Nanocrystals; Nanotechnology; Neptunium; Plutonium; Research Article; Thorium; Uranium; 双氧铀; 合成技术; 混合氧化物; 磁学性质; 纳米晶体; 结构表征; 钍; 锕系元素; nanocrystal; mixed oxide; thorium; magnetism; non-aqueous synthesis; nanoparticle; uranium
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-013-0379-6

One of the primary aims of the actinide community within nanoscience is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile synthesis techniques dedicated to the formation of new actinide-based nano-objects （e.g., nanocrystals） are necessary. Hence, a ＂library＂ dedicated to the preparation of various actinidebased nanoscale building blocks is currently being developed. Nanoscale building blocks with tunable sizes, shapes and compositions are of prime importance. So far, the non-aqueous synthesis method in highly coordinating organic media is the only approach which has demonstrated the capability to provide size and shape control of actinide-based nanocrystals （both for thorium and uranium, and recently extended to neptunium and plutonium）. In this paper, we demonstrate that the non-aqueous approach is also well adapted to control the chemical composition of the nanocrystals obtained when mixing two different actinides. Indeed, the controlled hot co-injection of thorium acetylacetonate and uranyl acetate （together with additional capping agents） into benzyl ether can be used to synthesize thorium/uranium mixed oxide nanocrystals covering the full compositional spectrum. Additionally, we found that both size and shape are modified as a function of the thorium：uranium ratio. Finally, the magnetic properties of the different thorium/uranium mixed oxide nanocrystals were investigated. Contrary to several reports, we did not observe any ferromagnetic behavior. As a consequence, ferromagnetism cannot be described as a universal feature of nanocrystals of non-magnetic oxides as recently claimed in the literature.