The positron lifetimes of Ni 36Nb 24Zr 40 and (Ni 0.36Nb 0.24Zr 0.40) 90H 10 glassy alloys are almost the same but longer than those of pure Zr, Nb, and Ni crystals, indicating that they have higher density of vacancies with smaller size than in crystals. The coincidence Doppler broadening spectrum for both specimens shows that the contribution of Ni around the vacancies is lower than that of Zr and Nb, suggesting that hydrogen atoms favour to exist between Ni atoms comprising neighboring distorted icosahedral Zr 5Ni 5Nb 3 clusters. Thus, these results provide a substitute model of quantum dot tunneling along Ni-H-Ni atomic bond arrays among the clusters.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)