Metallic colloids in lithium oxide after electron irradiation

Lithium oxide (Li(2)O) has been studied in various contexts for more than two decades. Previous work on electron-irradiated Li(2)O crystals has demonstrated a simultaneous formation of two populations of colloids of metallic lithium, one of which is associated with oxygen bubbles and a typical size of > 10 mu m, the other one consisting of nanoclusters in the range of < 10 nm. The latter one has been explored in detail in a recent neutron scattering study of the associated distortion field. In the present work we extend the investigation of the two colloid distributions down to low temperatures close to 30 K. The question of a possible occurrence of small (as opposed to the well-known large) oxygen clusters is discussed and it is found that if such clusters exist at all, their concentration must be very low. (C) 2004 Elsevier B. V. All rights reserved.