Solvothermal synthesis, optical and magnetic properties of nanocrystalline Cd1−xMnxO (0.04 < x = 0.10) solid solutions

Nanoparticles of Cd1−xMnxO (0.04 < x = 0.10) have been prepared using solvothermal method through oxalate precursor route for the first time. Thermal decomposition of the oxalate precursors were studied by thermogravimetric analysis in nitrogen atmosphere and their kinetics has also been studied. Kinetic analysis according to Freeman and Carroll method showed that activation energy increases on increasing the Mn concentration. X-ray diffraction studies showed the formation of cubic structure of all the oxides with no additional peaks corresponding to secondary phase. Optical absorption measurements showed an energy band gap which increased with Mn doping. This simple and inexpensive method was found to be effective in the preparation of Mn-doped CdO nanoparticles in the range of 18–25 nm. Particle size decreased from 25 to 18 nm and likely the surface area increases from 56 to 107 m2 g−1 on increasing the Mn concentration from 4 wt.% to 10 wt.%. Magnetic measurements revealed the paramagnetic behavior with no sign of long-range order above 5 K.

► Monophasic Mn-doped CdO nanoparticles by solvothermal method for first time.
► Plausible reaction mechanism using thermogravimetric analysis.
► High surface area with small particle size obtained.
► Decrease in band gap with increasing Mn concentration.
► Paramagnetism with no sign of long-range order above 5 K.