Injection of self-interstitials into a single crystal of nickel: One-interstitial vs. two-interstitial model

In conclusion, the C-defect in nickel consists of an 111In atom at a tetrahedral lattice position, at the centre of a tetrahedron formed by four neighbouring vacant lattice sites. Since the C-defect is formed at about 350 K by thermally activated trapping of migrating lattice defects, the migrating species at that temperature can only be of vacancy type. As stressed by Frank and Seeger, this outcome directly disproves the two-interstitial model because it denies vacancy migration in recovery stage III. (orig./TW)