Chemical disorder as engineering tool for spin-polarizationin Mn3Ga-based Heusler systems

TL;DR

This paper demonstrates that chemical disorder, introduced through non-stoichiometric variations, can be used to enhance spin-polarization in Mn3Ga Heusler systems by manipulating electron mobility, supported by first-principles calculations.

Contribution

It presents a novel approach to engineer spin-polarization via chemical disorder in Mn3Ga, supported by first-principles conductivity calculations.

Findings

Small substitution of transition elements increases spin-polarization.

Chemical disorder effectively modulates electron mobility.

First-principles calculations confirm the mechanism.

Abstract

Our study highlights spin-polarization mechanisms in metals, by focusing on the mobilities of conducting electrons with different spins instead of their quantities. Here, we engineer electron mobility by applying chemical disorder induced by non-stoichiometric variations. As a practical example, we discuss the scheme that establishes such variations in tetragonal Mn3Ga Heusler material. We justify this approach using first-principles calculations of the spin-projected conductivity components based on the Kubo-Greenwood formalism. It follows that, in majority of the cases, even a small substitution of some other transition element instead of Mn may lead to a substantial increase in spin-polarization along the tetragonal axis.