Mossbauer effect and X-ray diffraction investigation of Si-Fe thin films

An X-ray diffraction and 57 Fe Mossbauer spectroscopy investigation of Si100-xFex(0 < x < 80) thin films prepared by combinatorial sputtering methods is reported. Resulting Mossbauer spectra were fit to Voigt-based distributions of quadrupole doublets for paramagnetic spectral components and Zeeman split sextets for ferromagnetic spectral components. In conjunction with the X-ray measurements, these results show that the Si- rich films are a mixture of dilute Fe in amorphous Si and an approximately equiatomic amorphous SiFe phase. Fe-rich films show the presence of a ferromagnetically ordered phase. For x < 73, this ferromagnetic phase is amorphous or nanostructured and for x >= 73, the phase is shown to be a crystalline bcc phase. Results are discussed in terms of short-range structural ordering in these alloys.