Hydrothermal Synthesis and Characterization of Nanostructured Cobalt-Doped Tin Dioxide

Abstract

Nanostructured materials based on cobalt-doped SnO₂ have been prepared through alkaline hydrothermal treatment of aqueous solutions of inorganic Sn(II) and Co(II) salts. It has been shown that raising the cobalt concentration to 10 wt % leads to significant changes in the morphology and ferromagnetic properties of the synthesis products. The phase composition of the materials corresponds to tetragonal SnO₂ with the rutile structure. Calcination above 450°C leads to Co₂SnO₄ formation. The saturation magnetization and magnetic susceptibility of the materials vary nonlinearly with the amount of cobalt added to the reaction mixture. The nanostructured material obtained in the presence of ~6 wt % Co has an anomalously high room-temperature saturation magnetization, ~3.5 emu/g, which is almost two orders of magnitude higher than that of highly dispersed powders with a similar composition prepared via chemical precipitation.