Magnetic properties and structure of nanocrystalline Fe70Al30 alloy prepared by mechanosynthesis

Nanocrystalline powder samples of Fe70Al30 alloy were prepared by the mechanical alloying method. X-ray diffraction, Mossbauer and magnetic studies indicated that the ferromagnetic solid solution with BCC structure was formed with an increase in milling time. The magnetic ordering temperature T-c of the nanocrystalline mechanically alloyed Fe70Al30 was larger than that of the corresponding alloy prepared by rapid quenching, while the average magnetic moment per Fe atom in the investigated milling alloy was smaller than in cold-worked Fe70Al30 alloy. The high value of the hyperfine magnetic field of about 29 T measured in the Fe70Al30 alloy was explained in the frame of a local environment model, where five or more Fe atoms in the nearest neighbourhood of Fe-57 constitute the most probable configuration. (C) 1998 Elsevier Science B.V. All rights reserved.