Optical and magnetic properties of Sn1−xMnxO2 dilute magnetic semiconductor nanoparticles

Sn1−xMnxO2 (x = 0.05, 0.10 and 0.15) nanoparticles with tetragonal structure have been successfully synthesized by solvothermal method using oxalate precursor route. The oxalate precursors and its corresponding oxides were characterized by powder X-ray diffraction (PXRD), thermogravimetric (TG), fourier transform infrared (FTIR) and transmission electron microscopic (TEM) studies. PXRD studies showed the highly crystalline and monophasic nature of the solid solutions. The shifting of X-ray reflections towards higher angle is attributed to the incorporation of Mn2+ ions in SnO2 host lattice. The average particle size was found to be in the range of 5-11 nm. Reflectance measurements showed blue shift in energy band gap which increases with increasing Mn2+ concentration. Surface area of these nanoparticles (59-388 m2/g) was found to be high which increases with increasing the dopant ion concentration. Mn-doped SnO2 showed distinct magnetic behaviour with different manganese concentration. Sn1−xMnxO2 (x = 0.05 and 0.10) revealed the parasitic ferromagnetism, however on increasing x = 0.15, sample showed paramagnetic behaviour.