ROOM TEMPERATURE FERROMAGNETIC BEHAVIOUR OF INDIUM-DOPED SnO2 DILUTE MAGNETIC SEMICONDUCTOR NANOCRYSTALLINE THIN FILMS

Pure and Indium (In) doped SnO2 nanocrystalline thin films have been fabricated using sol-gel technique. The effect of In-doping on structural, optical and magnetic properties has been studied. Scanning electron microscopy (SEM) study reveals that the grains of pure and doped SnO2 possesses spherical symmetry. X-ray diffraction (XRD) study reveals that pure and In-doped SnO2 thin films possess rutile structure having tetragonal phase. UV-visible study suggests that with In-doping in SnO2, the value of the band gap first increases (upto 5% In-concentration) but further increase in concentration of In to 25% leads to decrease in band gap. It has been found from the room temperature magnetic study that pure and In-doped SnO2 thin films show ferromagnetic behaviour, however with 5% In-doping saturation magnetization value increased. The observed ferromagnetic behaviour may be due to the defects and oxygen vacancies.