Study of the enhancement of the magnetic properties of Fe70Al30−xSix alloys in the order-disorder transition

The aim of this work is to study the influence of the coexistence of different ordered structures on the evolution of the magnetism in the order-disorder transition produced by crushing and mechanical milling in the intermetallic Fe70Al30−xSix alloys. First, XRD measurements show that the three ordered samples have both D03 and B2 structures simultaneously and that the disordering process takes place in two stages. In the first one the D03 structure starts to disorder and in the second one, once the D03 structure has almost disappeared, the B2 starts to disorder. Second, Mössbauer spectroscopy and magnetic measurements show that there is an enhancement of the magnetic properties related to the structure change and to the increase of the lattice parameter in the order-disorder transition. The change of the magnetic behaviour is linked to the disordering of B2 structure in these alloys.