Effects of Sm3+ Doping on Dielectric Properties of Anatase TiO2 Nanoparticles Synthesized by a Low-Temperature Hydrothermal Method

Abstract

Samarium-doped thermally stable TiO2 nanoparticles in the anatase phase have been synthesized by a low-temperature hydrothermal method. The formation of the anatase phase has been investigated by x-ray diffraction. Thermogravimetry and differential thermal analysis have been used for thermal studies. The morphology and composition of synthesized powders have been studied using scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectroscopy. Surface areas were studied by the Brunauer–Emmett–Teller method. Dielectric properties were studied for dopant levels of 0.2 mol% and 0.5 mol% at 300 K in the frequency range of 42 Hz to 5 MHz. At low frequency, charge carriers at the grain boundary produce interfacial polarization giving rise to a high dielectric constant (e¢), which is significantly reduced by doping with samarium ions (Sm 3+ ). Strong frequency dependence of the dielectric loss was also observed for each concentration. Conductivity studies showed that the reduction in conductivity is due to the decrease in particle size with the increase in Sm 3+ dopant level.