The influence of annealing atmosphere on the properties of Zn1-xCoxO powders as seen by EPR spectroscopy.

This paper reports the influence of the annealing in air and argon atmosphere on the structural and magnetic characteristics of Co-doped ZnO powders. XRD studies reveal a wurzite- type structure, while the formation of Co3O4 secondary phase was evidenced by Raman spectroscopy only for the sample annealed in air. A ferromagnetic behavior was observed for the sample annealed in air atmosphere and this behavior was explained. The sample annealed in argon atmosphere presents a paramagnetic behavior. [ABSTRACT FROM AUTHOR]