Subsolidus phase relations in the Y₂O₃-Eu₂O₃- SnO₂ ternary system and their luminescent properties

Subsolidus phase relations in the ternary system Y₂O₃-Eu₂O₃- SnO₂ have been investigated by means of X-ray powder diffraction. The samples are prepared by solid-state chemical reaction. The (Y_1-xEu_x)₂Sn₂ O₇ and (Y_1-xEu_x)₂O₃ binary systems form complete solid solutions with pyrochlore-type and cubic structures, respectively. The characteristic photoluminescence peaks observed from (Y_1-xEu_x)₂Sn₂ O₇ and (Y_1-xEu_x)₂O₃ compounds correspond to Eu³⁺ intra-4fⁿ shell transitions. The difference between the emission and excitation spectra of (Y_1-xEu_x)₂Sn₂ O₇ and (Y_1-xEu_x)₂O₃ can be explained by considering the surroundings of crystallographic site occupied by Eu³⁺.