Adriana Popa, Dana Toloman, Oana Raita, Alexandru Biris, Gheorghe Borodi, Thikra Mustafa, Fumiya Watanabe, Alexandru Biris, Alexandru Darabont, Liviu Giurgiu
October 15, 2011
Structural, morphological and magnetic properties of Zn1−xCoxO (x = 0.01 and 0.03) powdered materials are presented. XRD studies reveal a wurtzite-type structure, while the formation of a Co3O4 secondary phase was evidenced by Raman spectroscopy. A ferromagnetic behaviour with low Curie temperature was evidenced by Electron Paramagnetic Resonance (EPR) investigation. We suggest that the origin of the ferromagnetism in Zn1−xCoxO powders is probably due to the presence of the mixed cation valence of Co ions via a double-exchange mechanism rather than the real doping effect.