Nanowires formation and the origin of ferromagnetism in a diluted magnetic oxide

The ferromagnetic response from Co-doped CeO2 epilayers is shown to be linked to the formation of Co metallic nanowires (diameters in the 3-7 nm range) within the oxide matrix. These results (i) illustrate the key role of the shape anisotropy of metallic inclusions in diluted magnetic oxides (DMO), (ii) stress the importance to monitor the out-of-plane response of DMO, and (iii) suggest that some dilute systems previously thought to be intrinsic ferromagnet may be reexamined. (C) 2009 American Institute of Physics. [doi:10.1063/1.3250173]