On the energy transfer in LiMgPO4 doped with rare-earth elements

Abstract

The phosphates LiMgPO₄:RE (RE – Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm) with an olivine-type orthorhombic structure were synthesized by the conventional solid state reaction route and their optical properties were examined by the experimental and theoretical methods. In this work, we showed that the radioluminescence and thermoluminescence spectra of irradiated LiMgPO₄:RE (RE = Sm, Gd, Tb, Dy, Tm) consist of lines reflecting 4f–4f transitions in the rare-earth element. For LiMgPO₄:RE (RE = Nd, Ho, Er), they coincide with the spectrum of the phosphate matrix with two broad bands at 360 nm and 650 nm but are much more intense. A model of energy transfer is proposed to explain this phenomenon. It is shown that the model is confirmed by the features of photoluminescence in doped LiMgPO₄ and by the results of ab initio calculations.