High-amplitude ultrasonic vibrations, with frequencies of about 90kHz and amplitudes of up to 0.00034, were used to obtain oscillatory stresses of up to 14MPa in single crystals. This treatment led to the nucleation of cracks in annealed samples, and to the formation of dislocations in as-grown samples. The differing behaviors could be explained in terms of a reduction in free dislocation segment lengths, due to the diffusion of point defects towards dislocation lines during annealing.

G.V.Bušujeva, I.G.Gricaenko, G.M.Zinenkova, D.Klimm, P.Paufler, N.A.Tjapunina: Crystal Research and Technology, 1995, 30[4], 541-6