Mössbauer study of disordering in thin sputtered FeCo–SiO2 and FeCo films

Magnetron sputtered nanocrystalline thin Fe70Co30 metal and (Fe70Co30)95(SiO2)5 composite films show a differently broadened Mössbauer sextet, which is interpreted as an increase in CsCl-type solid solution ordering degree for the composite film. It is suggested that the effective magnetic field at iron nuclei increases by 15 kOe when an Fe atom is substituted by Co in the first coordination sphere. The ordering degree and the composite structure are shown to vary the lattice parameter by up to 0.5%.

► FeCo ordering degree varies Mössbauer sextet area.
► Hyperfine magnetic field increases stepwise under Fe substitution by Co.
► Hyperfine magnetic field of 371(3) kOe for Fe70Co30 is observed.
► Fe70Co30 lattice parameter varies up to 0.5% under composite film formation.