Room‐temperature ferromagnetism of ZnO/Zn 0.96 Mn 0.04 O core‐shell nanowimble

ZnO/Zn 0.96 Mn 0.04 O core‐shell nanowimbles were prepared in two steps: ZnO nanowimbles were synthesized by the standard thermal evaporation method, followed by depositing Zn 0.96 Mn 0.04 O onto the surface of the prepared ZnO nanowimble using an ultrahigh‐vacuum radio‐frequency magnetron sputtering system. The scanning electron microscopy images show that the morphology, the alignment and the uniformity of ZnO/Zn 0.96 Mn 0.04 O core‐shell nanowimbles are maintained as for the as‐prepared uncoated ZnO nanowimble, and the thickness of the magnetic Zn 0.96 Mn 0.04 O layer is about 20 nm. The XRD analysis reveals that Mn is incorporated well into the wurtzite ZnO without forming Mn oxide. The magnetic property measurement shows that the ZnO/Zn 0.96 Mn 0.04 O nanowimble is in the ferromagnetic state at room temperature. The coercive field turns out to be as large as 109 Oe and 153 Oe at 300 K and 10 K, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)