Ab-initio study of Fe-doped SnO2

A.M. MUDARRA NAVARRO, L.ERRICO, V. BILOVOL, A.F. CABRERA AND C.E. RODRÍGUEZ TORRES

Lima, Perú

Conferencia; XII Latin American Conference on the Applications of the Mossbauer Effect; 2010

In this work we report hyperfine parameters at the Fe site and the equilibrium interatomic distances calculated by ab-initio methods  for different impurity-oxygen vacancies configurations and for two Fe concentrations. The predictions are compared with experimental results obtained by Mössbauer and X-ray absorption spectroscopies for powder samples prepared by mechanosynthesis and sol-gel methods. The comparison between experimental and theoretical results for the hyperfine parameters (isomer shift and quadrupole splittings) and Fe-O bond-lengths allow us to conclude that the oxygen vacancies are located in the first coordination sphere of Fe atoms in all studied samples. Additionally, we study the magnetic alignment between Fe atoms considering different distributions of impurities in the SnO2 host. Our results show that the coupling is antiferromagnetic when the Fe atoms share oxygen atoms, but the system becomes ferromagnetic when vacancies are located between irons.