Ion-beam-mixed FeAl multilayers as studied by conversion electron Mössbauer spectroscopy and transmission electron microscopy

Abstract

Conversion electron Mössbauer spectroscopy (CEMS) and transmission electron microscopy (TEM) were combined so that the structural state of nearly equiatomic FeAl multilayers before and after Xe 3+ ion beam mixing could be studied; annealing was also carried out after the ion beam mixing so that the evolution of the structural state could be followed. The as-ion-beam-mixed material gave rise to a Mössbauer spectrum exhibiting a doublet the origin of which is probably a quadrupolar effect, and the lack of magnetic lines after irradiation at 77 K shows that the ion beam mixing procedure has a good efficiency on the atomic scale. The TEM observations indicate a close to b.c.c. disordered FeAl solid solution. From the CEMS-TEM study of annealing (300–750 K) after ion beam mixing it appears that the well-known B2 superstructure can be detected at temperatures as low as 470 K.