Abstract
We report ferromagnetism above in ( in at. %) sputtered thin films. For , a large magnetic moment of was observed, which decreases monotonically with increasing . We find evidence that the ferromagnetic moment is due to Cu-O planar nanophase inclusions in ZnO basal planes. The presence of CuO nanophase is confirmed by transmission electron microscopy, x-ray diffraction, and Raman spectroscopy studies. These inclusions are present even for , where Cu-O structures of a few nanometers in size are observed. Field-cooled and zero-field-cooled magnetization measurements show a bifurcation for temperatures below .
- Received 13 September 2006
DOI:https://doi.org/10.1103/PhysRevB.75.054423
©2007 American Physical Society