Effect of atomic disorder on electronic, magnetic and electron-transport properties of Ti2MnAl

We report the combined computational and experimental study on the effect of atomic disorder on electronic, magnetic, and electron-transport properties of Ti2MnAl Heusler alloy. Ti2MnAl is predicted to exhibit spin-gapless semiconducting behavior in the inverted cubic crystal structure, while the regular cubic structure is essentially non-spin-polarized and non-magnetic. Here, we analyze three types of atomic disorder, namely, A2, B2, and D0(3), which are commonly observed in Heusler alloys. Our first-principles calculations indicate that all three types of disorder have a relatively small effect on a non-spin-polarized nature of Ti2MnAl in the regular cubic crystal (prototype Cu2MnAl) structure. At the same time, the inverted cubic phase (prototype Hg2TiCu) retains a significant degree of spin-polarization in A2 and B2 disordered structures. In particular, A2 and B2 types of disorder of the inverted cubic phase result in a spin-polarization of about 50% and 74%, respectively. The D0(3) disordered inverted phase has a significantly smaller spin-polarization of less than 10%. All considered structures align ferrimagnetically, except the B2-disordered and non-disordered regular cubic phases, which are non-magnetic. Our experimental results are consistent with the predicted properties of Ti2MnAl with partial A2 and B2 disorder types. While atomic disorder in a considered system should be minimized or avoided for practical implementations, its type may play a decisive role for potential applications in spin-based electronics. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the effect of atomic disorder on the properties of Ti2MnAl Heusler alloy. Different types of disorder have varying impacts on the spin-polarization and magnetism of the alloy. A2 and B2 disorder types in the inverted cubic phase show higher spin-polarization, while D0(3) disorder has a smaller effect.