Journal of Applied Physics vol:98 issue:7 pages:1-5
In order to reveal cationic site preference in beta-FeSi2, Co-substituted samples synthesized by various techniques such as molecular beam epitaxy, ion implantation, and chemical vapor transport were investigated by Fe-57 conversion electron Mossbauer (CEM) as well as Co-57 Mossbauer emission (ME) spectroscopy. Literature on the structure of beta-FeSi2 is somewhat contradictory, especially on the point of the population of the two iron sites in the orthorhombic structure. Co-57 ME and Fe-57 CEM spectra both showed two quadrupole split spectral components in the crystalline phase. Hyperfine parameters indicate that Co atoms substitute Fe in both Fe positions in the orthorhombic lattice. The aim of the present study was to get reliable results on the relative population of the two iron sites and determine the substitution of the iron sites by Co atoms in the beta-FeSi2 lattice. The relative intensities of the two components in the absorption and emission Mossbauer spectra were found to be very similar for the samples prepared by different techniques, indicating a homogeneous distribution of Co on both Fe sites. (c) 2005 American Institute of Physics.