Fabrication and scintillation properties of highly transparent Pr:LuAG ceramics using Sc,La-based isovalent sintering aids

The use of aliovalent sintering aids, especially TEOS, for scintillation ceramics preparation caused serious problems due to the need for charge compensation. Isovalent ions, on the other hand, do not cause such a problem and remain a new field to be explored. By using La2O3 and Sc2O3 isovalent sintering aids, we succeeded to produce Pr:LuAG ceramics with pure LuAG phase, good microstructure, and characterized by high optical quality with 80% transmittance in the visible range. Luminescence and scintillation properties were also investigated and turned out to be similar to those of previously studied transparent ceramics obtained with aliovalent sintering agents. Thermoluminescence data show the presence of several trapping states experiencing a disordered surrounding. It can be concluded that sintering aids, regardless of their valence, introduce local disorder due to their different radius with respect to that of the lattice ions resulting in the appearance of a UV emission and decrease of Pr3+ fast 5d-4f luminescence intensity. The aspects of energy transfer and trapping due to sintering aids in LuAG lattices are discussed.