DIPOLE AND INTERFACIAL POLARIZATION PHENOMENA IN NATURAL SINGLE-CRYSTAL CALCITE STUDIED BY THE THERMALLY STIMULATED DEPOLARIZATION CURRENTSMETHOD

The low-temperature thermal depolarization spectrum of natural single- crystal calcite exhibits two relaxation mechanisms: the lower temperat ure (LT) one located at 188 K and the medium temperature (MT) one loca ted at 230 K. Extensive thermally stimulated depolarization current (T SDC) experiments proved that the LT band is related to the rotation of defect dipoles, while the MT one to the interfacial polarization. A t heoretical quantitative model, which involves the SiO2 inclusions in t he matrix, is developed and successfully interprets the appearance and the behavior of the MT band. [S0163-1829(98)02940-3].