Vacancy-Mediated Magnetism in Pure Copper Oxide Nanoparticles
Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, 730000, Lanzhou, People’s Republic of China
Nanoscale Research Letters 2010, 5:769-772 doi:10.1007/s11671-010-9555-8Published: 16 February 2010
Room temperature ferromagnetism (RTF) is observed in pure copper oxide (CuO) nanoparticles which were prepared by precipitation method with the post-annealing in air without any ferromagnetic dopant. X-ray photoelectron spectroscopy (XPS) result indicates that the mixture valence states of Cu1+ and Cu2+ ions exist at the surface of the particles. Vacuum annealing enhances the ferromagnetism (FM) of CuO nanoparticles, while oxygen atmosphere annealing reduces it. The origin of FM is suggested to the oxygen vacancies at the surface/or interface of the particles. Such a ferromagnet without the presence of any transition metal could be a very good option for a class of spintronics.