Influence of Ti addition on the room temperature ferromagnetism of tin oxide (SnO2) nanocrystal

Nano-crystalline Sn1−xTixO2 (x=0.00, 0.02, 0.05 and 0.07) particles were synthesized by the sol-gel method without any surfactant and dispersant material. The X-ray diffraction (XRD) pattern shows the formation of the tetragonal rutile phase structure for the undoped SnO2 nanoparticle and Ti doping does not alter the structure of undoped tin oxide. Due to quantum confinement effect, a larger optical band gap for as-synthesized materials was found. Vibrating sample magnetometer (VSM) result demonstrates the undoped and 2% Ti doped SnO2 samples exhibit perfect room temperature ferromagnetism (RTFM) but 5% and 7% of Ti doped samples show a weak ferromagnetism with diamagnetic contribution. The ferromagnetic property of the material was initiated with the help of oxygen vacancy. The amount of oxygen vacancy present in the samples were identified from the photoluminescence spectra and the value of oxygen vacancy decreased with increasing Ti concentration.