2H NMR study of sites and dynamics of deuterium and their isotope effects in Ti0.1V0.9HxDy (x+y≈0.7)

Ti-0.1 V0.9HXDy (x+yapproximate to0.7) alloys have been studied by H-2 NMR. H-2 spectra revealed the sites of deuterium. In the H-rich samples, D atoms occupy both the octahedral (0) and tetrahedral (T) sites. In the deuteride, the D-rich sample and the sample of [H]/[D]=1, D atoms occupy the T sites. The activation energies of D diffusion were estimated from the temperature and frequency dependence of 2 H spin-lattice relaxation times (T-1). The activation energy is higher in the O sites than in the T sites, as is the case for H diffusion. The activation energy in the O sites is higher for D diffusion than for H diffusion, and this isotope effect is negligible in the T sites. (C) 2002 Elsevier Science B.V. All rights reserved.