Room temperature ferromagnetism in hydrothermally grown Ni and Cu co-doped ZnO nanorods

The fabrication and magnetic characteristics of Ni and Cu co-doped ZnO nanorods are reported. The Ni and Cu co-doped ZnO nanorods are synthesized by a facile hydrothermal method. Structural characterizations reveal that Ni and Cu ions enter into ZnO lattices without any secondary phases. SEM images show that they are regular nanorods. Magnetic measurements indicate that the obtained rod arrays exhibit room-temperature ferromagnetic behaviors. The exchange interaction between free delocalized carriers (holes from valence band) and the localized d spins of Ni and Cu ions is considered as the cause of the room-temperature ferromagnetism.