Structural, Electronic, and Magnetic Properties of Mn۲NbAl۱-xSix (x=۰.۰–۱.۰) Alloys

The structural, electronic and magnetic properties of the novel Mn۲NbAl۱-xSix (x=۰.۰–۱.۰) alloys were investigated by using the density functional theory. The formation and cohesive energy results confirm that all members of these series are thermodynamically stable, but the Hg۲CuTi-type structure has lower stability compared to the Cu۲MnAl-type structure. The results also reveal that with increment of Si content, the lattice constant decreases linearly from ۶.۰۱ to ۵.۸۸ Å, while the bulk modulus increases. The total spin magnetic moment decreases from ۲.۰۰ µB (for x = ۰.۰) to ۰.۹۹ µB (for x = ۱.۰). The results of electronic structure show that the alloys with x = ۰.۰, ۰.۲۵ and x = ۰.۵۰ have a half-metallic nature with a real gap in the down-spin band, and ۱۰۰% spin polarization. For other alloys, the spin polarization decreased with increasing x from ۰.۷۵ to ۱.۰. Although ۱۰۰% spin polarization was not found for all members of these series, it is quite high value which can be used in industries.

کلیدواژه ها:

Magnetic Intermetallic ، density functional theory ، Electronic Structure ، Half-metallic