CONICET | Buscador de Institutos y Recursos Humanos

Trabajo presentado en forma de poster durante la reunion 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, as for example in catalysis, but also because of their potential use in spintronic devices. Fe-doped TiO2 and SnO2 are also of significant interest in magnetism. Among other techniques, Mössbauer Spectroscopy was largely applied to study these systems. However, contradictory results were obtained, and a unique consensus on the hyperfine parameters associated to substitutional Fe atoms in the rutile or anatase structures has not been achieved yet. 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. In addition, relatively little attention was given to the local structure around the Fe dopant. Knowledge of the local environment of the Fe dopant is essential in order to understand the mechanisms giving rise to the magnetic order in these compounds. Very recently, we demonstrated the capability of the ab initio full-potential augmented plane wave plus local orbital (APW+LO) method to predict the hyperfine parameters at Fe-impurity sites in anatase TiO2. Following this approach, in this work we present a series of calculations, performed with the APW+LO methods, of the hyperfine parameters at Fe impurities in SnO2. Calculations were performed as a function of the Fe-dopant and oxygen vacancies concentrations and distributions, assuming substitutional and interstitial site localizations for Fe in the structure. Our results are compared with available experimental data.