High-temperature ferromagnetism in Mn-doped ZnO nanowires

We have observed ferromagnetism in dilute (similar to 1-4 at. %) Mn-doped crystalline ZnO nanowires at temperatures up to 400 K. Arrays of freestanding single crystal ZnO:Mn nanowires were fabricated by Au-catalyzed vapor-liquid-solid growth. Structure and compositional analyses revealed that Mn was incorporated into the ZnO lattice. From the observed saturation magnetization, the magnetic moment per Mn atom is estimated to be between 0.3 mu(B) and 1.2 mu(B). Photoluminescence measurements show a strong suppression of defect related midgap emission, indicative of an interplay between Mn doping and native point defects. (c) 2006 American Institute of Physics.