Thermally stimulated depolarization and infrared studies in single-crystal dolomite (CaMg(CO3)2) Original Research Article

The thermally stimulated depolarization current technique is employed so as to study the dipole relaxation in dolomite. We traced two dominant low-temperature dispersions; one located at 140 K and another at 188 K. The first is characterized by the distribution in the relaxation time and the latter one has single-valued relaxation parameters. Standard characterization techniques and annealing treatments on dolomite samples with different micro-structural features showed that the dipoles contributing to the 140 K peak are matrix defects, rather than hydrophilic sites in the pore network. The infrared spectroscopy established the absence of water molecules and the presence of hydroxyls, which probably constitute one type of defect dipoles.