A key to room-temperature ferromagnetism in Fe-doped ZnO: Cu

Successful synthesis of room-temperature ferromagnetic semiconductors, Zn1-xFexO, is reported. The essential ingredient in achieving room-temperature ferromagnetism in bulk Zn1-xFexO was found to be additional Cu doping. A transition temperature as high as 550 K was obtained in Zn0.94Fe0.05Cu0.01O; the saturation magnetization at room temperature reached a value of 0.75mu(B) per Fe. A large magnetoresistance was also observed below 100 K. (C) 2002 American Institute of Physics.