Muon diffusion in intermetallic compounds of the MoSi2-type structure

The localization and diffusion of positive muons are studied in three binary metallic systems, Zr2Cu, Hf2Cu and Ti2Cu, presenting the MoSi2-type structure. Zero-field μSR measurements are interpreted as the muons being static in the Tb/Ob interstitial site at low temperatures and, as the temperature is increased, starting diffusing through the network of Tb sites around the Ob site, until they reach a state occupying simultaneously the four Tb sites. Long-range diffusion is observed above 300 K. Activation energies for the lower-temperature diffusion processes are obtained. The results are interpreted in terms of the lattice structure characteristics. (author)