Mössbauer and FP-LAPW study of Fe-doped TiO2 and SnO2.

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

CAC (CNEA), Buenos Aires , Argentina

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

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

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.             There is a great deal of new experimental and theoretical work on these TM-doped systems (TM= Mn, Co, Fe, Ni, Cu), focused on their magnetic properties. In the case of Fe doping, Mössbauer studies were performed in order to elucidate the local atomic structures associated to the observed interactions. Despite the several reports published on quadrupole splitting data, a unique consensus on the hyperfine parameters associated to Fe substitutional in the rutile structure has not been achieved yet. Several questions remain open concerning the Fe dopants location in the host structure, and/or the short range orders around impurities, as well as the assignment of the observed hyperfine interactions.                In 2002 we demonstrated the capability of the ab initio full potential linearized augmented plane waves (FP-LAPW) method to predict the hyperfine parameters at impurity sites. Following this approach, in this work we present a comparative experimental Mössbauer spectroscopy and theoretical FP-LAPW calculations of the hyperfine parameters at Fe impurity in the rutile phase of TiO2 and SnO2.