Actinide and RE ions in ThO2 single crystals have been studied by means of EPR spectroscopy. Samples were prepared by high temperature solution growth using Pb2V2O7 as flux. In both 0.1% and 1% neptunium doped samples, X-band spectra do not show evidence of Np4+ resonances down to 3 K; however, the spectra of Er3+, Yb3+ and Gd3+ in cubic sites have been recorded. Moreover, Pu3+ resonances, together with the ΔM ≠ ± 1 Gd3+ transitions, have been identified in the sample with lower neptunium concentration. Dy3+ 0.1% doped ThO2 crystals show both cubic and trigonal spectra, with a well-resolved hyperfine structure due to the odd isotopes. Analysis of this structure for the observed cubic transition allows us to indicate the role of the nuclear electric quadrupole transition.
|Tipologia ministeriale:||Articolo su rivista|
|Appare nelle tipologie:||1.1 Articolo su rivista|