In order to determine the parameters of H motion in the cubic (C15-type) Laves phase ZrMo2, we have performed quasielastic neutron scattering measurements and nuclear-magnetic-resonance measurements of the proton spin-lattice relaxation rate on ZrMo2Hx (0.3 < x < 1.0) in the temperature range 10–430 K. The diffusive motion of hydrogen in this system can be described in terms of two jump processes: the fast localized H motion within the hexagons formed by interstitial g (Zr2Mo2) sites and the slower hopping from one hexagon to the other. The hopping rate τ-1l of the faster process is found to be of the order of 1010s-1 at 300 K. The characteristic frequency τ-1d of the slower process at the same temperature is about 6 × 107s-1. Comparison of the motional parameters of hydrogen in ZrMo2Hx with those in the related C15-type systems TaV2Hx and ZrCr2Hx shows that the value of τd/τl for ZrMo2Hx lies between the corresponding values for TaV2Hx and ZrCr2Hx. This is consistent with the changes in the ratio of g-g distances r1 (within the hexagons) and r2 (between different hexagons).
|Original language||English (US)|
|Number of pages||7|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 1 1999|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics