Thermally stimulated relaxation in Fe-doped SrTiO₃ systems: I. Single crystals

Thermally stimulated depolarization current (TSDC) measurements were carried out on 0.1% and 1% iron (Fe)-doped SrTiO₃ crystals to study various effects that are not detected from other electrical characterization methods such as impedance spectroscopy. Using this TSDC technique, the origins of different relaxations in Fe-doped SrTiO₃ crystals were identified, and activation energy of the orientated dipole, energy depth of trap site, and trap density in the polarized samples were then estimated from TSDC measurements. From the resulting activation energy of 0.65±0.08 eV of trap charges, these traps are assigned to oxygen vacancy-iron defect complexes. The high-temperature peak at temperature ∼190°C is assigned to the relaxation current of oxygen vacancies and the calculated activation energy of 0.91±0.05 eV is in good agreement with the literature data.