Formation of large climb loops at decorated dislocations in gadolinium gallium garnet

Dislocations in large crystals of gadolinium gallium garnet (Gd3Ga5O12 or GGG) are sometimes decorated with precipitate particles. Examination of these particles in a polarizing light microscope reveals that they are frequently encircled by large (≈ 0.1 mm in diameter) climb loops on {111} and {110} planes. The loops are of interstitial type. They increase the dislocation density of the sample, and modify the stress field of the decorated dislocation. They also provide sites for further precipitation, and lead to clusters of etch pits where a single long decorated dislocation meets the sample surface. Copyright © 1976 WILEY‐VCH Verlag GmbH & Co. KGaA