Positive muon diffusion in mixed Nb-hydrides, NbHxDy

Positive muons have been used to monitor the proton and deuteron mobilities in mixed, concentrated NbHxDy hydrides, with x+y= constant. The mobility of the muons decreases linearly with increasing D-content, which is expected if the protons and the deuterons move in an uncorrelated fashion. Combined with other evidence which suggests that such correlations exist, the present observation may be interpreted as due to a destruction of a correlated motion of H's or D's in the vicinity of the muons