Annealing effect on structural, optical, and magnetic behaviour in nanocrystalline SnO<SUB align="right">2

SnO2 nanopowder samples are successfully synthesised by using the auto combustion technique and calcinated from 650°C to 950°C for 5 h. The Structural, optical, and magnetic properties of the samples have been investigated. X-ray diffraction patterns have revealed the rutile tetragonal structure of the synthesised SnO2 nanoparticles with higher crystallinity and also the structure is not affected due to temperature variation. The formation of point defects like oxygen vacancies is confirmed from Raman spectroscopy. The FTIR spectra have displayed the presence of Sn-O bonding vibrations in the samples which complements the Raman spectroscopy results. Field Emission scanning electron microscope (FESEM) micrograph has revealed the presence of voids in between the spherical grains. From UV-visible absorption spectroscopy, a decrease in band gap is observed, because of non-stoichiometric defects. The VSM results have confirmed the ferromagnetic nature of SnO2 samples at room temperature which indicates SnO2 behaves like an oxide diluted magnetic semiconductor (ODMS).