Magnetic properties of (Mn, Al) doped SnO2 nanoparticles: synthesis and characterization

Abstract

Pure and (Mn, Al) co-doped SnO2 nanoparticles were synthesized using co-precipitation method. Different concentrations of Mn (1, 3, 5 mol%) were doped into SnO2 at 5 mol% constant concentration of Al. The X-ray diffraction (XRD) studies revealed the formation of single tetragonal rutile-type phase in pure and (Mn, Al) doped SnO2 nanoparticles. The particle sizes were in the range of 20–30 nm, as calculated from the XRD data. Raman studies revealed that the pure and (Mn, Al) doped SnO2 nanoparticles have active modes at 150 (B1g), 306 (Eu), 476 (Eg), 625 (A1g) and 776 cm−1 (B2g) corresponding to tetragonal rutile-type phase SnO2. The SEM micrographs show that the surface morphology of samples was formed by non-uniform spherical in shape particles. The chemical composition of samples was analyzed by EDAX spectra analysis. The presence of Sn4+, Al3+, O−2 and Mn2+ ions was confirmed in the prepared samples. The observation of TEM micrographs confirmed the non-uniform spherical shape surface morphology of nanoparticles and their sizes about 20–30 nm. The UV–VIS absorption spectra show absorption edge at ~ 320 nm, whereas the photoluminescence spectra show the emission peaks at 419, 420, 442, 445 and 462 nm under the excitation at 350 nm. The vibrating sample magnetometer shows diamagnetic nature for pure SnO2 and Ferro magnetism for co-doped SnO2 samples. The ferromagnetism increased in (Mn, Al) co-doped SnO2 samples at higher Mn concentrations.