Films of Cu-doped ZnO, exhibiting room-temperature ferromagnetism, were prepared by using the filtered cathodic vacuum arc technique. The films deposited at room temperature had the stronger magnetic moment (0.40μ/Cu), when compared with samples prepared at high temperatures. The observed strong ferromagnetism in the room-temperature deposited films was partly associated with Zn interstitials. The degradation of the magnetic moment in films prepared at high temperatures, and annealed at high temperatures, was attributed to the out-diffusion of Zn interstitials.

Zn-Interstitial-Enhanced Ferromagnetism in Cu-Doped ZnO Films. Herng, T.S., Lau, S.P., Yu, S.F., Chen, J.S., Teng, K.S.: Journal of Magnetism and Magnetic Materials, 2007, 315[2], 107-10