Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1622617 | Journal of Alloys and Compounds | 2009 | 5 Pages |
Abstract
The hydrogen diffusivity D in C14-type HfCr2H0.4 has been measured by means of the pulsed-field-gradient nuclear magnetic resonance over the temperature range 141-428 K. The temperature dependence of D in this range is found to deviate strongly from the Arrhenius behavior. This is consistent with a quantum nature of H diffusion in HfCr2Hx. Measurements of the proton spin-spin relaxation rate R2 in HfCr2Hx (x = 0.4, 0.6 and 0.74) have revealed the anomalous R2 peak near 230 K for all the samples studied. The experimental results indicate that this peak originates from slow fluctuations of the proton resonance frequency. Such fluctuations are expected for protons diffusing through a spatially inhomogeneous medium on the length scale of about 500 Ã
. The origin of the inhomogeneity suggested by the R2 data in HfCr2Hx remains to be elucidated.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
A.V. Skripov, K. Ulrich, F. Grinberg, A.V. Soloninin, A.L. Buzlukov,