Determination of Diffusion Coefficients of Self-Interstitials in Ice with a New Method of Observing Climb of Dislocations by X-Ray Topography

Abstract

The diffusion coefficients of self-interstitials in ice were determined from the growth processes of interstitial-type dislocation loops and dipoles introduced by cooling on the basis of the fact that the growth takes place by the diffusion of excess interstitials to dislocations. The time variation of their size was obtained by in situ X-ray topographic observations using a high-power X-ray source. By combining the obtained diffusion coefficients and the equilibrium concentration of interstitials previously obtained, it is possible to determine the self-diffusion coefficient D _s in ice. The value of D _s obtained by this method and its activation energy E coincide well with those determined by tracer experiments. This result confirms the interstitial mechanism for self-diffusion in ice.