Doping dependent room-temperature ferromagnetism and structural properties of dilute magnetic semiconductor ZnO:Cu2+ nanorods

Copper doped ZnO nanoparticles were synthesized by the chemical technique based on the hydrothermal method. The crystallite structure, morphology and size were determined by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) for different doping percentages of Cu2+(1-10%). TEM/SEM images showed formation of uniform nanorods, the aspect ratio of which varied with doping percentage of Cu2+. The wurtzite structure of ZnO gradually degrades witht he increasing Cu2+ doping concentration and an additional CuO associated diffraction peak was observed above 8% of Cu2+ doping. The change in magnetic behavior of the nanoparticles of ZnO with varying Cu2+ doping concentrations was investigated using a vibrating sample magnetometer (VSM). Initially these nanoparticles showed strong room-temperature ferromagnetic behavior, however at higher doping percentage of copper the ferromagnetic behavior was suppressed and paramagnetic nature was enhanced. (C) 2009 Elsevier B.V. All rights reserved.