Photoluminescence and magnetism in Co-doped ZnO powder

Spindle-like ZnO doped with 2-5 at% cobalt powders were prepared by a low temperature aqueous solution method. The structural and magnetic properties of the products were investigated. The obtained products were identified to be of hexagonal wurtzite structure without any impurity phase. Also, the Co was incorporated in the ZnO lattice as Co2+ and substituted for the Zn site with no evidence of metallic Co. Ferromagnetic behaviour was clearly observed at room temperature for the Co-doped samples. Photoluminescence intensity due to the vacancies varies with the Co concentration, and the ferromagnetism moment increases with the increment of oxygen vacancies.