EXAFS study of the local environment of impurities in doped TiO2 thin films.

C. RODRÍGUEZ TORRES; F. CABRERA; L. A. ERRICO; F. GOLMAR; M. RENTERÍA; F. H. SÁNCHEZ

CAC (CNEA), Buenos Aires , Argentina

Congreso; "At the Frontiers of Condensed Matter Physics III"; 2006

CAC (CNEA) y Depto. de Física (UBA), Argentina

In order to clarify the role of transition metal impurities in diluted magnetic semiconductors (DMS) it is crucial to determine the local environment of these magnetic or non magnetic impurities. In this work we present an EXAFS (Extended X-Ray Absorption Fine Structure) and XANES (X-ray Absorption Near Edge Spectroscopy) characterization of the local environment of M-doped anatase TiO2 thin film (M= Co, Ni, Cu, and Zn). The films were deposited on LaAlO3 (001) substrates by Pulsed Laser Deposition using a Nd:YAG laser. They were transparent, strongly textured (showing only the [001] reflections of the anatase structure) and ferromagnetic at room temperature. We did not found the presence of metallic clusters in any case. The oxidation state is 2+ and the local coordination with the oxygen nearest-neighbours  is similar as in  MO (CoO, NiO, CuO, and ZnO, respectively) but, except in the Cu case, the similarity with these oxides only exists in the short range scale.