Magnetic properties of Gd2O3 doped UO2 nanoparticles

DINA TOBIA; ANALÍA SOLDATI; AFRA FERNÁNDEZ ZÚVICH; IGNACIO GANA WATKINS; JULIÁN MILANO; ELIN WINKLER

San Carlos de Bariloche

Simposio; XXIII Latin American Symposium on Solid State Physics; 2018

The study of lanthanides and actinides oxides has attracted a lot of interest in the scientific community as they present complex electronic structures due to the interaction between the spin and the different orbital degrees of freedom, conferring these materials unusual and varied properties. Recently, much of the attention was focused on the production and study of actinides nanoparticles (NPs), specially regarding the uranium species, due to their potential applications in the nuclear energy production. Gd is usually incorporated into the UO2 nuclear fuel as a burnable poison, because of its high cross section for neutron absorption. However, the fabrication process of the solid solution (U, Gd)O2 and the amount of Gd incorporated could affect some physical and chemical properties, that can eventually alter the proper and safe performance of this fuel in reactors, as well as the stability in storage and disposal conditions. UO2 nanoparticles doped with 4, 8, 10 and 15 wt% Gd2O3 were synthesized by the "Reverse Strike" co- precipitation method. A thorough study of the structural and chemical homogeneity properties was recently conducted [1], indicating that the nanoparticles have homogenous composition at the micrometer scale. In this work we present a study of the magnetic properties through magnetization and electron paramagnetic resonance spectroscopy (EPR) experiments. Particularly, EPR spectroscopy allows to obtain microscopic information of the crystalline environment and spin-lattice relaxation that complements the magnetic and structural characterization. The studies signal the presence of different magnetic interacting mechanisms, depending on Gd concentration. We discuss the influence of the synthesis route, grain size and Gd concentration on the obtained results.[1] A. L. Soldati et al., J. Nucl. Mater. 479 (2016) 436-446