Enhanced magnetism in Cr-doped ZnO nanoparticles with nitrogen co-doping synthesized using sol-gel technique

Pure ZnO and 2 % Cr-doped ZnO nanoparticles were synthesized by sol-gel technique. Powder X-ray diffraction reveals that Cr incorporates into the ZnO crystal lattice without disturbing the original hexagonal structure. Transmission electron microscopy measurements show that the average size of these nanoparticles is in the range 20-25 nm. Pure ZnO nanoparticles exhibit diamagnetism while Cr-doped ZnO exhibit saturated hysteresis loop at room temperature indicating ferromagnetic behavior. Nitrogen co-doping along with Cr in ZnO shows enhanced ferromagnetism with small antiferromagnetism.