The influence of annealing on the magnetism of Fe-doped ZnO prepared by mechanical alloying

The magnetic properties of Fe-doped ZnO prepared by mechanical alloying are reported before and after annealing in vacuum, air and hydrogen. The as-milled sample is magnetic with saturation magnetization Ms≈0.25μB/Fe. It is noteworthy that the magnetism and Curie temperature increased by heat treated in hydrogen. No secondary phase is detected in the as-milled and H2-annealed samples by the measurements of X-ray diffraction, X-ray photoelectron spectroscopy and Mössbauer spectra, suggesting the ferromagnetism in these powders are intrinsic.