Observation of lithium colloid melting in irradiated Li2O

When irradiated with energetic electrons near room temperature Li2O Single crystals exhibit metallic Li colloids, as shown by ESR (electron spin reson ance) and Li-7-NMR experiments. These colloids were established as being of two types of very different sizes. ESR experiments performed above room temperature, in the range up to 300 de grees C show melting of the metallic colloids as observed on the line param eters, affecting simultaneously the width and the intensity of the ESR sign al. The phenomenon is complicated by the fact that annealing effects of the metallic colloids are superimposed on the purely thermal behaviour. We performed also DSC (differential scanning calorimetry) experiments which are manifesting directly the reversible melting of the colloids; from the integrated intensity of the DSC peaks, we could deduce the lithium metal co ncentration, which is in good agreement with the value obtained from the ES R signal intensity.