Study of the polarizable centers in single crystal dolomite (CaMg(CO3)2) rich in Fe3+ impurities by thermally stimulated depolarization current spectroscopy

Trivalent iron cations show a strong preference for substituting the magnesium cations of the mixed crystal dolomite. In the present work, we identify dielectric relaxation mechanisms, which correspond to different dipole defect configuration and investigate their dynamics by employing thermally stimulated depolarization current technique. A selective polarization scheme was successfully employed to resolve different mechanisms, which overlap strongly. Two dominant relaxations are located at 205 and 247 K, respectively, and are related to the presence of iron in the dolomite matrix. The signals were analyzed assuming a normal distribution in the activation energy values. Different dipole defect configurations are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.