Tunable mechanical and half-metallic properties of Mn2-XFe1+XSi alloys: A first principles investigation

摘要

The structural, mechanical, electronic, and magnetic properties of Mn2-XFe1+XSi (X = 0, 0.25, 0.5, 0.75, 1) Heusler alloys were studied in the framework of the density functional theory (DFT). The results show that Mn2XFe1+XSi compounds are mechanically and dynamically stable with Hg2CuTi type (X = 0, 0.25 and 0.5) and Cu2MnAl type (X = 0.75 and 1); the volume of the series compounds decreases and they can change from brittle to ductile as Fe content increases. All the compounds have half-metallic properties and their Fermi levels gradually move to the middle of the spin-down band gap as X increases. The magnetic moment of Mn2-XFe1+XSi mainly arises from more Mn-d orbitals than Fe-d orbitals and satisfies the extended Slater-Pauling rule; the energy gaps are generated from the split in the energy level of d-orbitals of atoms on A, C sites and then hybrid with the d-orbitals of atoms on B sites.