Thorium/uranium mixed oxide nanocrystals: Synthesis, structural characterization and magnetic properties
thorium, uranium, mixed oxide, non-aqueous synthesis, nanoparticle, nanocrystal, magnetism
ABSTRACT 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 actinide- based 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 com¬positional 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.
Tsinghua University Press
Damien Hudry,Jean-Christophe Griveau,Christos Apostolidis,Olaf Walter,Eric Colineau,Gert Rasmussen,Di Wang,Venkata Sai Kiran Chakravadhaluna,Eglantine Courtois,Christian Kübel,Daniel Meyer, Thorium/uranium mixed oxide nanocrystals: Synthesis, structural characterization and magnetic properties. NanoRes.2014, 7(1): 119-131