Fe-doped rutile SnO2 and TiO2: local structure vs. hyperfine parameters

A. M. MUDARRA NAVARRO; C. E. RODRÍGUEZ TORRES; A. F. CABRERA; M. WEISSMANN; L. A. ERRICO

Medellin

Congreso; XIII Latin American Conference on the Applications of Mossbauer Effect. LACAME 2012; 2012

During the last years the study of transition-metal-doped TiO2 and SnO2 semiconductors has become a topic of interest, not only because of the many current industrial applications of these materials but also because of their potential use in spintronic devices Among other techniques, Mössbauer Spectroscopy was largely applied to study these systems. However, contradictory results were obtained, and several questions remain open concerning the location of the Fe dopants in the host structure, and/or the short range orders around impurities, as well as the assignment of the observed hyperfine interactions. We present here an ab initio study (using the full-potential augmented plane wave plus local orbital, APW+LO method) of Fe-doped rutile SnO2 and TiO2. We performed calculations of hyperfine parameters at Fe impurities in SnO2 and TiO2 as a function of the Fe-dopant, oxygen vacancies concentrations and distribution of impurities and oxygen vacancies in the hosts and assuming substitutional and interstitial site localizations for Fe in the structures. The magnetic allignment and the role of the different variables on it is discussed and compared with available experimental data.