Comparison of magnetic properties of nanopowders of carbon-doped and pure ZnO prepared by pulsed electron beam evaporation

•ZnO doping with carbon materials were prepared by pulsed electron beam evaporation.•Magnetization of the annealed ZnO sample produced in vacuum is two times higher than magnetization of the annealed sample produced in the air atmosphere.•FM response of carbon-doped samples was 5 times higher than the magnetic response of non-doped samples. The single-phase crystal ZnO-C nanopowders with the hexagonal wurtzite structure and a low carbon dopant content (under 0.25wt%) were produced. The production of the ferromagnetic nanopowders was done by electron beam evaporation of mechanical mixtures of non-magnetic micron ZnO powders and carbon in a vacuum at RT. The subsequent annealing of evaporation products in air was produced at the temperature of 773K. The ferromagnetic response of the doped ZnO-C NP has exceeded that of the pristine ZnO NP by 5 times. The anhysteretic form of ZnO-C NP magnetization curves reveals the tendency of samples to superparamagnetism. The abnormal behavior of the ZnO-C (% xC=0.25wt%) sample magnetization curve in the magnetic field of 2.4T can be attributed to the metamagnetic transformation associated with the bimodal distribution of the ZnO ferromagnetic phase in accordance with the SEM analysis.