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Title:Oxygen defect origin of ferromagnetism in ZnCoO
Authors:Ruairi Hanafin and Stefano Sanvito, 2010
Abstract: Density function theory calculations have shown that the magnetism in ZnO:Co originates from the interplay between Co2+ and Co2+–oxygen vacancy (CoV) pairs. Co2+ can interact only at short range while long-range magnetic interaction can be achieved for CoV via conduction electrons at moderate n-doping. This mechanism however is still insufficient to explain room temperature ferromagnetism due to the prohibitive concentrations of vacancies needed. The experimental findings may then be explained by a combination of our proposed mechanism and the formation of blocked superparamagnetic clusters. Here we examine the role played by inhomogeneous distributions of magnetic impurities and their impact on the observed magnetic properties. It is found that a modest tendency towards clustering can yield a considerable increase in the magnetization and the critical temperature.
ICHEC Project:Theory of ferromagnetism in diluted and defective oxides
Publication:Journal of Magnetism and Magnetic Materials Volume 322, Issues 9-12, May-June 2010, Pages 1209-1211
URL: http://linkinghub.elsevier.com/retrieve/pii/S0304885309005617
Keywords: Dilute magnetic semiconductors; monte Carlo; Blocked super paramagnetism
Status: Published

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