Effect of ferromagnetic properties in Al-doped Zn1−xCoxO nanowires synthesized by water-assistance reactive vapor deposition

Abstract

The Zn1−xCoxO and Al-doped Zn1−xCoxO nanowires have been synthesized by the water-assistance reactive vapor deposition method. No Co precipitates appeared in the both kinds of ZnO nanowires according to the results observed by high-resolution transmission electron microscope, x-ray diffraction, and electron energy-loss spectroscopy, revealing that the magnetism of the ZnO nanowires was independent of the Co precipitates. The Al-doped Zn1−xCoxO nanowires show much stronger ferromagnetism than Zn1−xCoxO nanowires in the temperature range of 4–350 K. It is believed that the ferromagnetism in Zn1−xCoxO nanowires could be enhanced by Al doping to introduce donor carriers. Moreover, a multiple mechanism for the ferromagnetism of Al-doped Zn1−xCoxO nanowires is discussed.