Investigation of the physical properties of Fe:TiO2-diluted magnetic semiconductor nanoparticles

Abstract

The structural, optical, magnetic, and electrical properties of sol–gel-derived Ti_1−xFe_xO₂ (0.00 ≤ x ≤ 0.05) nanoparticles were investigated. Rietveld refinement of the X-ray diffraction data and TEM measurements were carried out to analyze the crystalline structure and quality of all the samples. Raman spectroscopy revealed a decrease in intensity and broadening of the characteristics peaks of Fe-doped TiO₂ with respect to those of the pristine sample, which signifies a structural distortion of the lattices. FT-IR, UV-vis, and PL spectroscopy were used to investigate the optical properties. Magnetic measurements showed a weak ferromagnetism at room temperature in both the pristine and Fe-doped TiO₂ (x = 0, 0.02, and 0.05) nanoparticles. Temperature-dependent resistivity measurements showed the semiconducting nature of the samples and revealed that the thermally activated conduction (Arrhenius) mechanism is valid in the high-temperature region, whereas Mott variable range hopping (VRH) mechanism is valid in the low-temperature region. Dielectric properties of the samples were studied as a function of temperature in the frequency range of 1 kHz to 1 MHz.