Paper eintragenThermally activated processes were investigated by applying acoustic spectroscopic techniques to polycrystalline samples. The measurements were carried out between 1.1 and 600K, in the kHz range, and the concentrations of interstitial H and O in annealed and deformed samples were varied. Four processes were observed, in addition to the main dissipation peak around room temperature. These were due to the formation or dissolution of H pairs. A process at liquid He temperatures was attributed to H tunnelling. Processes which occurred below 300K were explained in terms of the motion of interstitial H which was trapped by O or was dragged by dislocations. A large relaxation which was detected around 450K was attributed to the hopping of O in a solid solution.

G.Cannelli, R.Cantelli, F.Cordero, F.Trequattrini: Physical Review B, 1997, 55[22], 14865-71