Single crystals of Y2O3 partially-stabilized material were deformed at 1400C and studied by means of high-voltage electron microscopy. It was found that, at an yttria concentration of 6.8mol%, elongated planar defects with an antiphase boundary-like contrast appeared on four {101) planes. This unusual <101]{101) glide system was activated due to a more favorable atomic arrangement of the planar defects on {101) planes instead of {010) planes.

D.Baither, B.Baufeld, U.Messerschmidt: Journal of the American Ceramic Society, 1995, 78[5], 1375-9