The effect of defects on the magnetic properties and spin polarization of Ti2FeAl Heusler alloy

• The perfect Ti2FeAl Heusler alloy exhibits a ferromagnetic half-metallic behavior.
• Among swap defect, only the total magnetic moment of the Ti2–Al swap defected is close to the perfect alloy.
• All defected structures destroy the half-metallicity.
• Only AlTi1 and AlTi2 antisite and Fe vacancy defects maintain relatively high spin polarization.

The effect of antisite, swap and vacancy defects on the magnetic properties and spin-polarization of the full-Heusler Ti2FeAl alloy with the Hg2CuTi-type structure is studied by using the first-principles calculations within density functional theory. The perfect Ti2FeAl Heusler alloy exhibits a ferromagnetic half-metallic behavior with the total magnetic moment of 1µΒ and indirect band gap of 0.543 eV. Among swap defect, only the total magnetic moment of the Ti2–Al swap defected is close to the perfect alloy. All defected structures destroy the half-metallicity and only AlTi1 and AlTi2 antisite and Fe vacancy defects maintain relatively high spin polarization.