Adriana Popa, Dana Toloman, Oana Raita, Alexandru Biris, Gheorghe Borodi, Thikra Mustafa, Fumiya Watanabe, Alexandru Biris, Alexandru Darabont, Liviu Giurgiu
October 15, 2011
Abstract
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.