Study of Semimagnetic Mn-Doped WO₃ Nanoparticles Synthesised by Precipitation Method: Hydrogenation Creates a Promising DMS

Abstract Tungsten oxide (WO₃) nanoparticles doped with different amounts of manganese ions (W_1−xMn_xO₃, where x = 0.011, 0.022 and 0.044) were synthesised by hydraulic acid-assisted precipitation, followed by thermal calcinations. The powders were characterised by X-ray fluorescence (XRF), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS) and magnetic measurements. The monoclinic structure at room temperature (∼293 K) found for un-doped WO₃ was preserved even with Mn doping. However, doping with Mn ions caused decease in unit-cell volume and slight increase in crystallite size (CS) of host WO₃. The hydrogenation was observed to corrode the crystallites without changing in crystalline structure. Controllable room-temperature ferromagnetic (RT-FM) properties were obviously observed with hydrogenated WO₃ doped with Mn. In addition, there existed an optimum doping concentration of Mn in WO₃ to obtain superior FM properties. Therefore, Mn-doped WO₃ nanopowders, owning to these amazingly tunable magnetic properties, could be considered a potential candidate for many applications partially required FM properties such as optical phosphors and catalysts.