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

X-ray diffraction and Mossbauer spectroscopy techniques at room temperature are applied to find out the influence of the sequential substitution of Ni by Mn in ternary Fe-65(Ni1-xMnx)(35) (0 less than or equal to x less than or equal to 1) alloys on the structure and the local magnetic order in similar to 5 and similar to 15 nm particles prepared by evaporation of foil samples in Ar atmosphere. Small (similar to 5 nm) particles exhibit the bcc structure in contrast to the bulk ternary alloys having the fee structure. The increase of the size up to similar to 15 nm as well as the increase of Ni content leads to the appearance of an admixture of the fee phase in X-ray patterns. Analysis of the Mossbauer spectra with consideration of the X-ray data, indicates the existence of the high-temperature fee structure of particles in two spin states. (C) 1999 Elsevier Science Ltd. All rights reserved.