HIGH-TEMPERATURE DEFECT SPECTROSCOPY IN IONIC-CRYSTALS

The first direct NMR spectroscopic evidence of defects in crystalline Li2O powders containing aliovalent impurities is reported. Quadrupole- perturbed Li-7 satellite transitions are seen above 600 K, which clear ly arise from interaction of lithium defects. At about 900 K structure in the satellite transitions indicates two distinct quadrupolar inter actions. The relative intensity of the satellites decreases with incre asing temperature, which is interpreted as thermal dissociation of an impurity-vacancy complex.