Evidence by EPR of ferromagnetic phase in Mn-doped ZnO nanoparticles annealed at different temperatures

► ZMO nanoparticles annealed at different temperatures were prepared. ► The particles sizes were investigated by TEM. ► Annealing temperature influence on vibration modes were evidenced by Raman effects. ► For the sample annealed at 425 °C, a ferromagnetic phase was identified by EPR. ► The ferromagnetic phase origins were discussed.