Novel magnetic properties of Co3O4 nanowires

It is found that the Co3O4 nanowires, prepared by directly oxygenating cobalt foil, can keep an antiferromagnetic order until room temperature, quite different from other Co3O4 materials. The opposite behaviors of the M(T) curves under 100 and 6500 Oe, and the irreversible magnetic contributions at room temperature are observed. Detailed structural analysis and the splitting of energy levels in different crystalline fields show that the distortions of the crystal lattice make some nonmagnetic Co3+ ions have magnetic moment, which may possibly be the source for these novel behaviors. (C) 2009 Elsevier Ltd. All rights reserved.