Synthesis of undoped and M-doped ZnO (M = Co, Mn) nanopowder in water using microwave irradiation

Undoped and M-doped ZnO (M = Co, Mn) nanopowders have been successfully synthesized by microwave-assisted approach using Zn(NO3)2.2H2O and NaOH. The results obtained from X-ray diffraction (XRD) analysis and the transmission electron microscopy (TEM) showed that the mean particle size was about 10–15 nm. The XRD analysis of the synthesized samples also showed a single phase ZnO structure without any additional phase. Magnetic property studies of the as-prepared M-doped ZnO (M = Co, Mn) samples showed them to be paramagnetic material. However, thermal annealing in air of particular samples at 800°C for 3 h resulted in transforming the samples into a room temperature ferromagnetic material.