Mössbauer Study of Fe _xMn_0.65−xAl_0.35 Disordered Alloys Series

Melted alloys of the Fe_xMn_0.65−xAl_0.35 disordered system, 0.25≤x≤0.65, were studied by Mössbauer spectroscopy and X-ray diffraction. All the alloys exhibit the bcc structure with a nearly constant lattice parameter (2.92 Å). Mössbauer studies at 300 K show that in the 0.25≤x≤0.45 range the alloys are paramagnetic while in the 0.50≤x≤0.65 range, they are ferromagnetic and the mean hyperfine field increases when x increases. At 77 K, Mössbauer studies show that the alloy with x=0.25 presents weak magnetic character that is consistent with an antiferromagnetic behavior due to the high Mn content, while those with 0.30≤x≤0.40 are paramagnetic. Finally, in the 0.45≤x≤0.65 range the alloys are F and the mean field increases when the Fe content increases. The linear decrease of isomer shift with x shows that the increase of the Fe content produces an increasing density of s electrons in the Fe nucleus.