Room-temperature ferromagnetism observed in Fe-doped NiO

Here we report a kind of diluted magnetic semiconductor (DMS) system, i.e., Fe-doped NiO. Monophase Ni1-xFexO (x=0-0.02) was synthesized by using a chemical coprecipitation method and post-thermal decomposition processing. Pure NiO without Fe doped is antiferromagnetic. The results demonstrated the samples with Fe doped were ferromagnetic at room temperature, which is stronger than most DMS oxide systems, e.g., Mn or Ni-doped ZnO, and Co-doped TiO2 reported recently. The effect of Fe doping was discussed and relevant mechanism was proposed, by comparing with previous studies of finite size effect in NiO nanoparticles and other DMS systems. (C) 2005 American Institute of Physics.