Electronic and magnetic properties of Fe3−xCrxSi ordered alloys from first principles

Density functional theory calculations are performed to investigate the electronic and magnetic properties of Fe3−xCrxSi alloys with Cr concentration in the range of 0.25 ≤ x ≤ 2.75. The L21 phase is found to be a more stable one in comparison with the A15 phase for x ≤ 1.50 beyond which the A15 phase becomes more stable. Alloys with the stable L21 phase are found to be metallic for x ≤ 0.75, however, a half metallic behavior is found at x = 1.00, 1.25, and 1.50 with band gaps of 0.60, 0.24, and 0.21 eV, respectively. In contrast, all A15 structures are found to be metallic. The total magnetic moments are found to decrease for L21 phase from 14.4 μB/cell at x = 0.25 to zero at x = 2.00 with non-integer values for the metallic structures and integer values for the half-metallic. However, a monotonic decrease is found for the case of A15 phase with values larger than those of L21 phase.