The thermally stimulated current processes which were induced by ultraviolet light and X-irradiation at low temperatures, in oxidized Mg-doped single crystals, were studied at temperatures of between 80 and 300K. It was found that the main thermally stimulated current process exhibited the same behavior as the main thermally stimulated polarization process with respect to the peak temperature, activation energy, and sample-thickness and thermal-treatment dependences. It was concluded that this thermally stimulated current process, like the thermally stimulated polarization one, arose from the thermally activated ionization of MgAlx centers and was due to the existence of blocking contacts at the sample/electrode interfaces. The observed irradiation-induced decrease in the thermally stimulated depolarization currents could also be explained in terms of the stimulated dielectric relaxation-current theory which had previously been applied to the thermally stimulated polarization and thermally stimulated depolarization phenomena in other metal/insulator/metal systems with blocking.

Ionizing Irradiation-Induced Thermally Stimulated Currents in Al2O3:Mg. R.Vila, M.J.De Castro: Physical Review B, 1999, 59[11], 7480-5