Inelastic neutron scattering study of magnetic excitations in uranium phosphates
Résumé
The results of inelastic neutron scattering experiments performed on the compounds U1−xThx(UO2)(PO4)2 (x=0,0.5) and U2O(PO4)2 are presented. The partial substitution of uranium with thorium in the former compound was performed to decouple the magnetic dimers and observe a pure single-ion behaviour. The INS data indicate that the main interaction, responsible for the magnetic excitations observed in all of the compounds examined, is the crystal field due to the oxygen ligand cage that surrounds the U4+ sites, rather than the exchange interaction between magnetic ions.