Raman spectra, photoluminescence and ferromagnetism of pure, Co and Fe doped SnO2 nanoparticles

The pure and transition metal (Co and Fe = 3 and 5 mol%) doped SnO2 nanoparticles have been synthesized by a chemical route using polyvinyl alcohol as surfactant. These nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL) and magnetic measurements. The XRD patterns show that all the samples have tetragonal rutile structure without any extra phase and the value of average particle size using FWHM lies within 12–29 nm is also confirmed by TEM. FTIR spectrum has been used to confirm the formation of SnO bond. Raman spectroscopy shows the intensity loss of classical cassiterite SnO2 vibration lines which is an indication of significant structural modifications. From PL, an intense blue luminescence centered at a wavelength ∼530 nm is observed in the prepared SnO2 nanoparticles, which is different from the yellow-red light emission observed in SnO2 nanostructures prepared by other methods. The strong blue luminescence from the as-grown SnO2 nanoparticles is attributed to oxygen-related defects that have been introduced during the growth process. These Co and Fe-doped SnO2 nanoparticles exhibit room temperature ferromagnetism and the value of their magnetic moment and phase transition temperature are sensitive to their size and stoichiometric ratio.