ZnO:Co Diluted magnetic Semiconductor or hybrid nanostructure for Spintronics?

F. GOLMAR; M. VILLAFUERTE; A. M. MUDARRA NAVARRO; C. E. RODRÍGUEZ TORRES; J. BARZOLA QUIQUIA; S. P. HELUANI; P. ESQUINAZI

Rio de Janeiro , Brasil

Conferencia; 11th International Conference on Advanced Materials; 2009

Unión Internacional de Sociedades de Investigación de Materiales (IUMRS)

We have studied the influence of intrinsic and extrinsic defects in the magnetic and electrical transport properties of Co-doped ZnO thin films. X ray absorption measurements show that Co substitute Zn in the ZnO structure and it is in the 2+ oxidation state. Magnetization (M) measurements show that doped samples are mainly paramagnetic. From M vs. H loops measured at 5 K we found that the values of the orbital L and spin S numbers are between 1 and 1.3 for L and S=3/2, in agreement with the representative values for isolated Co 2+. The obtained negative values of the Curie-Weiss temperatures indicate the existence of antiferromagnetic interactions.