Investigation of electron-irradiated zinc by diffuse x-ray scattering. II. Interstitial clustering during thermal annealing

The diffuse scattering intensity near Bragg reflections and the electrical-resistivity change following electron irradiation of zinc single crystals at 4.5 K were investigated during an isochronal annealing program. The initial Frenkel defect concentration varied between 18 and 120 ppm. At the end of recovery stage I (at 20 K) small interstitial agglomerates are formed. For the higher irradiation doses, cluster growth continues during recovery stage II up to an effective cluster size of $〈N〉\approx 10$ interstitials per agglomerate, but is strongly suppressed for the lowest initial defect concentration. The results are understood within the framework of the one-interstitial recovery model.