The magnetic relaxation method was applied to this cubic Laves phase in order to study low-temperature H diffusion. Two relaxation maxima were detected, at 82 and 108K; with mean activation enthalpies of 0.14 and 0.23eV. The associated pre-exponential factors were 10-7 and 4 x 10-10s, respectively. The 82K relaxation peak was attributed to the jumping of H during hydride formation in this temperature region. The 108K relaxation was attributed to an orientational after-effect in the absence of interactions between H atoms. This relaxation was attributed to atomic H jumps between the preferentially occupied interstitial tetrahedral sites that were formed by two Fe atoms and two Zr atoms. By means of thermal de-gassing, the long-range diffusion was found to be described by:

D (m2/s) = 3 x 10-8exp[-0.38(eV)/kT]

C.U.Maier, H.Kronmüller: Journal of Physics - Condensed Matter, 1992, 4[18], 4409-20

Table 207

Diffusion Parameters for H Migration in Fe90Zr10