Tunneling Relaxation of a Mixed Dumbbell in an Aluminum--Zinc Solid Solution. (Translation)

Below 250 deg K, the atoms in Al--Fe and Al--Zn solid solutions can form stable dumbbell pairs, oriented along the (100) axis. At these temperatures, diffusion of the foreign atoms is insignificant and the skewed dumbbells can be reorientated only between the six positions in the (100) axis. The energy barrier separating the equilibrium states of the dumbbells is approx 15 MeV. The kinetics of the reorientation mechanism have been studied by the low-frequency acoustic method. It is found that at < 20 deg K, the rate of relaxation increases with the reduction in temperature, consistent with a coherent diffusion tunnel relaxation mechanism. 9 ref.--A.S.W.