Room Temperature ferromagnetism in Cu Doped ZnO for spintronics

We report the growth of high quality Cu doped ZnO thin films by magnetron sputtering. Cu concentration has been varied over three orders of magnitude (0.01%-10%). Higher growth temperature ensures high level of Cu doping. The XPS measurements revealed that most of the Cu atoms have substituted into the ZnO lattice sites. Room temperature ferromagnetism, with magnetic moment initially increasing and then decreasing with Cu content, has been observed in the thin film. Oxygen vacancy and dopant activation play crucial role in the observed ferromagnetism.