Quenching Effects and Vacancy Characteristics in Zinc

Zinc single crystals and polycrystalline strips containing less than 10 ppm metallic impurities have been quenched from temperatures ranging between 20 and 240 °C to 4.2 K. Resistivity changes upon annealing were studied in the temperature range 70 to 450 K. The recovery spectrum is complicated by a cold work effect which is induced by the quenching and by the thermal cycling and superimposes on the elimination of the supersaturation concentration of vacancies. It was possible, however, to isolate the stage for the migration of single vacancies (around 180 K) and to measure the corresponding activation energy, (0.44 ± 0.03) eV. It is shown that, at low temperature, their migration proceeds essentially by nonbasal jumps. Furthermore, the vacancy formation energy has been determined to be (0.45 ± 0.05) eV. Des rubans monocristallins et polycristallins de zinc de haute purete (99,999%) ont ete trempes depuis des temperatures comprises entre 20 et 240 °C jusqu'a. 4,2 K. L'elimination de la sursaturation de lacunes a ete etudike au moyen de mesures de resistivite electrique, pour des temperatures de recuit echelonnkes entre 70 et 450 K. Le spectre de restauration se trouve complique par des effets d'ecrouissage de trempe et de cyclage thermique venant se superposer it l'hlimination des lacunes qui se produit entre 140 et 190 K. Nous avons pu neanmoins determiner l'energie de formation des lacunes (E = (0,45 ± 0,05) eV). L'analyse detaillee de la structure de la zone lacunaire a permis d'isoler le stade de migration des monolacunes. L'energie d'activation associee est de (0,44 ± 0,03) eV. A basse temperature, la migration des lacunes fait intervenir essentiellement le saut hors du plan de base.