Structure and local magnetic order in ultrafine particles of Fe65(Ni1−xMnx)35 (0≤x≤1) alloys

X-ray diffraction and Mössbauer spectroscopy techniques at room temperature are applied to find out the influence of the sequential substitution of Ni by Mn in ternary Fe65(Ni1−xMnx)35 (0≤x≤1) alloys on the structure and the local magnetic order in ∼5 and ∼15 nm particles prepared by evaporation of foil samples in Ar atmosphere. Small (∼5 nm) particles exhibit the bcc structure in contrast to the bulk ternary alloys having the fcc structure. The increase of the size up to ∼15 nm as well as the increase of Ni content leads to the appearance of an admixture of the fcc phase in X-ray patterns. Analysis of the Mössbauer spectra with consideration of the X-ray data, indicates the existence of the high-temperature fcc structure of particles in two spin states.