Nmr investigation of zrmn₂H_x and H₁Y₂H_2.1 Hydrides

The proton NMR relaxation times and Knight shifts are reported for the hydrides HfV₂H_2.1and ZrMnH_x, (x = 2.0, 2.45, 3.0, 3.2, 3.4) in the temperature range 160<T<400K using the spinecho method. The results are interpreted in terms of a diffusional relaxation mechanism as well as a magnetic relaxation mechanism for the hydride ZrMn₂Hx. The diffusional activation energy and the proton jump frequency were extracted from our measurements on HfV₂H_2.1.to be 4.3 kcal/mole and 3×10¹²s^-1 respectively. The diffusional activation energies are almost independent of hydrogen concentration, x, in ZrMn₂H_x, and equal to 3.7 ±0.6 kcal/mole approximately. Our data is compared to diffusion properties and sorption properties of other intermetallic hydrides.