DISORDER ENHANCED MAGNETIC MOMENT IN Fe2CrAl RIBBONS

The electronic structure and magnetic properties of Fe2CrAl have been investigated theoretically and experimentally. The theoretical calculations show that there is an energy gap in the minority-spin band in the electronic structure of ordered Fe2CrAl with the L21 structure and that the spin-polarization ratio is as high as 93%. The calculated total spin moment is 0.97 μB/f.u. However, in melt-spun Fe2CrAl ribbons, the B2 type structure, an atomic-site disordered L21 structure, is found and this atomic site disorder gives rise to a magnetic moment of 2.02 μB in the ribbons which is much higher than the theoretical value. The calculations prove that the enhanced magnetic moment is mainly due to the Fe–Cr and Fe–Al types of disorder. In contrast, the Cr–Al type disorder has little influence on the total spin moment and the spin-polarization ratio.