High-resolution Brillouin spectroscopy was used to characterize the elastic stiffness properties of consolidated nano-crystalline oxide samples, as well as those of the related monocrystals. Defect-enriched grain boundaries were considered to be sources of the extremely soft elastic properties of the nano-crystalline state.

Elastic Properties of Single-Crystalline and Consolidated Nano-Structured Yttrium Oxide at Room Temperature. J.Baller, J.K.Krüger, R.Birringer, C.Proust: Journal of Physics - Condensed Matter, 2000, 12[25], 5403-9