Structure, chemistry and luminescence properties of dielectric La Hf1-O films

Effect of Oxide Ion Distribution on a Uranium Structure in Highly U-Doped RE2Hf2O7 (RE = La and Gd) Nanoparticles

“…The LHO:U and GHO:U NPs were synthesized via the combined coprecipitation and molten-salt process with an equimolar La+U (or Gd+U) to Hf precursor ratio as described in the experimental section . All diffraction peaks of the XRD pattern of the LHO:U NPs (Figure (a)) are indexed to the cubic La 2 Hf 2 O 7 phase (ICDD 037-1040, space group: Fd3̅m ), indicating no impurity phases formation with up to 30 mol % U doping. The lattice parameters, calculated using Bragg’s law, are inversely proportional to the U concentration (Figure (c)) due to the smaller size of U ions compared with La, , confirming the incorporation of U into the LHO lattice in accordance with Vegard’s law.…”

“…To further highlight the effect of U doping on the host matrices, Rietveld refinement was performed. The XRD patterns for the undoped and 30 mol % U doped samples were refined using La 2 Hf 2 O 7 , Gd 2 Hf 2 O 7 , and Gd 0.44 Hf 0.56 O 1.78 as structural models. Due to the high U concentrations, attempts were made to refine these structures along with uranium oxide (i.e., UO 2 , UO 3 , U 3 O 8 , etc.)…”