Characterization of Sb-doped Bi2UO6 Solid Solutions by X-ray Diffraction and X-ray Absorption Spectroscopy

Abstract

XRD measurementsPowder X-ray diffraction studies on the samples were carried out using a Cu anode-based powder diffractometer operating in the Bragg-Brentano focusing geometry, and a curved crystal monochromator in the diffraction beam. The preparation and characterization of Sb-doped Bi2UO6 solid solutions, in a limited composition range, is reported for the first time. The solid solutions were prepared by solid-state reactions of Bi2O3, Sb2O3 and U3O8 in the required stoichiometry. The reaction products were characterized by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements at the Bi and U L3 edges. The XRD patterns indicate the precipitation of additional phases in the samples when Sb doping exceeds 4 at%. The chemical shifts of the Bi absorption edges in the samples, determined from the XANES spectra, show a systematic variation only up to 4 at% of Sb doping and support the results of XRD measurements. These observations are further supported by the local structure parameters obtained by analysis of the EXAFS spectra. The local structure of U is found to remain unchanged upon Sb doping indicating that Sb +3 ions replace Bi +3 during the doping of Bi2UO6 by Sb.

An insight into local environment of lanthanide ions in Sr2SiO4:Ln (Ln = Sm, Eu and Dy)

“…[15][16][17] 3. Our systems were equipped with double monochromators in either or both excitation and emission arms.…”

“…Other related information on instrumentation and sample preparation for EXAFS measurements is mentioned in our earlier reports. [15][16][17] 3. Results and discussion 3.1.…”