Room temperature ferromagnetism in Zn–Mn–O

Zn–Mn–O semiconductor crystallites with nominal manganese concentration x = 0.01 , 0.04 and 0.10 were synthesized by a solid state reaction method using oxalate precursors. A sintering procedure was carried out in air at 500 and 900  ∘C. The samples were investigated by X-ray diffraction, magnetization measurements and electron paramagnetic resonance. X-ray diffraction spectra reveal that the dominant crystal phase in the Zn–Mn–O system corresponds to the wurtzite structure of ZnO. Room temperature ferromagnetism is observed in Zn–Mn–O samples with manganese concentrations x = 0.01 and 0.04 sintered at low temperature (500  ∘C). Saturation magnetization in the x = 0.01 sample is found to be 0.03 μ B / Mn at T = 300 K . The ferromagnetic phase seems to be developed by Zn diffusion into Mn-oxide grains.