Positron depth-profiling was applied to monitor the effects of hydrogenation on Mg1-yTiy thin films. S-W diagrams and VEPFIT analysis of the depth-profiles demonstrated the homogeneity of most metal and metal hydride films. In contrast, Mg0.90Ti0.10H x films consisted of a double layer, with a thin unloaded Mg 0.90Ti0.10 or Mg-Ti-Pd alloy layer on top of a hydrogenated bottom layer. The metal-to-metal-hydride transformation of Mg domains in the nanoscale phase-segregated Mg-Ti films was monitored exclusively, enabled by the large difference in positron affinity for Mg and Ti. The changes in the Doppler broadening parameters revealed that the metal-insulator transition for fluorite MgH2 is similar to that for rutile MgH 2. Positron lifetime spectroscopy showed the presence of di-vacancies in the metal sub-lattice of as-deposited and hydrogenated Mg-Ti metal films, which may induce the fast hydrogen sorption kinetics of the fluorite MgH 2 phase.    «

Positron depth-profiling was applied to monitor the effects of hydrogenation on Mg1-yTiy thin films. S-W diagrams and VEPFIT analysis of the depth-profiles demonstrated the homogeneity of most metal and metal hydride films. In contrast, Mg0.90Ti0.10H x films consisted of a double layer, with a thin unloaded Mg 0.90Ti0.10 or Mg-Ti-Pd alloy layer on top of a hydrogenated bottom layer. The metal-to-metal-hydride transformation of Mg domains in the nanoscale phase-segregated Mg-Ti films was monitore...    »