THERMALLY STIMULATED POLARIZATION AND DEPOLARIZATION PROCESSES IN AL2O3-MG

Thermally stimulated polarization (TSP) and depolarization current mea surements in as-cut as well as in oxidized magnesium-doped aluminum ox ide show a huge peak at around 265 K, another one at 245 K, and a broa dband at higher temperatures. They are related to the presence of Mg-A l(x), centers (substitutional magnesium ions with a hole trapped at a neighboring oxygen ion) and originate from the thermally activated ion ization of these centers, which release holes. The current-voltage cur ves and the TSP results related to the main polarization process show that this is due to the formation of blocking contacts at the sample-e lectrode interfaces.