Paramagnetic surface defects in LiMgPO₄

摘要： The EPR spectra obtained at 300 K and 115 K are indicative of the existence of charged defects in LiMgPO4. The main imperfections are identified as a radical CO-3 (g=2) and a singly charged oxygen vacancy (g1=2.45, g2=2.20, g3=2.00). The presence of carbon-containing groups is proved by Raman spectroscopy. The assumption is made that the defects are located mainly on the surface of the grains. Thermoluminescent characteristics of LiMgPO4 annealed in atmospheres with different pO2 demonstrate that the surface defects impair the efficiency of LiMgPO4 as a dosimetric material.