Combinatorial material science studies of Fe-rich Fe-Al and Fe-Si thin films

Combinatorially sputtered libraries of Fe-rich thin films of the compositions Fe100−xAlx (with 2.9 < x < 30.9) and Fe100−xSix (with 2.0 < x < 22.8) have been prepared and investigated. Compositions have been measured by electron microprobe and crystal structures have been determined by X-ray diffraction. Room temperature 57Fe Mössbauer spectroscopy measurements have been conducted as a function of composition across the libraries. X-ray studies showed all compositions to be of the disordered bcc structure. 57Fe Mössbauer effect center shifts showed trends as a function of composition that were consistent with expectations based on changes in composition and local structure. 57Fe Mössbauer spectroscopy measurements show Fe hyperfine field distributions with a mean Fe field that decreased and a width that increased with decreasing Fe-content. Possible models for atomic order are discussed in the context of the features in the field distribution. For high Al or Si content alloys, the hyperfine field distribution became distinctly bimodal with mean hyperfine field values of the two components that agreed well with expectations for Fe in sites with localized D03 order. Results for Fe-Al and Fe-Si libraries are discussed in terms of literature results for combinatorially sputtered Fe-Ga libraries.