Disorder-Induced Enhancement of Magnetic Properties in Ball-Milled Fe2CrAl Alloy

First principles calculation for the energies and magnetic moments of Fe
₂
CrAl with various structures has been carried out. The contradiction between theoretical and experimental magnetic moment of Fe
₂
CrAl has been illustrated. The L2
₁
-based structure has the lowest energy and thus should be formed during synthesis, while the native magnetic Cr-clusters are responsible for the extra large magnetic moment. Based on these calculations, a metastable and partially disordered B2
_CD
structure has been achieved in a ball-milled Fe
₂
CrAl alloy. It shows a 300 K higher T
_C
and a 1.5 μ
_B
higher M
_S
, respectively, compared with the arc-melted samples with L2
₁
-based structures.