The high-temperature anelastic spectrum of Sc–O solid solutions was investigated in a polycrystalline sample for O concentrations of between 0.024 and 0.9at%O; as estimated by residual resistivity and intentional O doping. Two thermally-activated relaxation processes appeared near to 430 and 520K, for a vibration frequency of 3.5kHz. Both peaks were stable to thermal cycling, and their intensities increased with O content; thus indicating that they were due to O jumps. At lower temperatures, the process had an intensity that increased strongly with increasing temperature, when measured at a higher frequency (42kHz). This indicated that relaxation occurred between states which differed in energy by about 0.3eV. The peak could be described by a single relaxation time, and was interpreted as being due to the stress-induced hopping of single O atoms between non-equivalent tetrahedral and octahedral interstitial sites. The process, at high temperatures, was tentatively attributed to O pairs.

Mobility of Interstitial Oxygen in Scandium by Anelastic Spectroscopy. F.Trequattrini, F.Cordero, G.Cannelli, R.Cantelli: Solid State Communications, 2004, 129[4], 217-20. See also: Materials Science and Engineering A, 2004, 370[1-2], 93-5