First-Principles Investigation of Ti2.25Co0.75Si and Ti2.25Co0.75Si0.5X0.5 (X = As and Sb) Heusler Alloys: Spin-Polarized Electronic, Magnetic, and Mechanical Properties

Abstract

High-spin-polarized materials are the promising candidates in spintronic devices. Here, the spin-polarized electronic structure, magnetism, and mechanical properties of Ti2.25Co0.75Si and Ti2.25Co0.75Si0.5X0.5 (X = As and Sb) Heusler alloys were calculated by first-principles calculations. The results show that Ti2.25Co0.75Si and Ti2.25Co0.75Si0.5Sb0.5 are ferromagnetic half-metals with 100% spin polarization, while Ti2.25Co0.75Si0.5As0.5 is a zero-gap half-metal. The complete spin-polarized characteristics of Ti2.25Co0.75Si and Ti2.25Co0.75Si0.5X0.5 are confirmed to be robust to hydrostatic and uniaxial strains. The results of the elastic constants and phonon spectra demonstrate the mechanical and dynamic stabilities of Ti2.25Co0.75Si and Ti2.25Co0.75Si0.5X0.5 alloys. Furthermore, the magnetic anisotropy results show that the easy magnetic axis of Ti2.25Co0.75Si can be tuned from the in-plane direction to the out-of-plane one under the uniaxial strains. Ti2.25Co0.75Si and Ti2.25Co0.75Si0.5X0.5 (X = As and Sb) alloys are promising candidates for the potential application in spintronic devices.