Transport Spin Polarization of Noncollinear Antiferromagnetic Antiperovskites

TL;DR

This paper demonstrates that noncollinear antiferromagnetic ANMn3 antiperovskites can generate highly efficient spin-polarized currents, comparable to ferromagnets, making them promising for spintronic applications.

Contribution

It provides first-principles calculations showing the potential of ANMn3 antiperovskites as efficient spin sources with high spin polarization and charge-to-spin conversion efficiency.

Findings

Spin polarization in ANMn3 is comparable to ferromagnetic metals.

Out-of-plane transverse spin currents exhibit giant charge-to-spin conversion.

ANMn3 compounds are promising for spintronic device integration.

Abstract

Spin-polarized currents play a key role in spintronics. Recently, it has been found that antiferromagnets with a non-spin-degenerate band structure can efficiently spin-polarize electric currents, even though their net magnetization is zero. Among the antiferromagnetic metals with magnetic space group symmetry supporting this functionality, the noncollinear antiferromagnetic antiperovskites ANMn$_3$ (A = Ga, Ni, Sn, and Pt) are especially promising. This is due to their high N\'eel temperatures and a good lattice match to perovskite oxide substrates, offering possibilities of high structural quality heterostructures based on these materials. Here, we investigate the spin polarization of antiferromagnetic ANMn$_3$ metals using first-principles density functional theory calculations. We find that the spin polarization of the longitudinal currents in these materials is comparable to that in widely used ferromagnetic metals, and thus can be exploited in magnetic tunnel junctions and spin transfer torque devices. Moreover, for certain film growth directions, the out-of-plane transverse spin currents with a giant charge-to-spin conversion efficiency can be achieved, implying that the ANMn$_3$ antiperovskites can be used as efficient spin sources. These properties make ANMn$_3$ compounds promising for application in spintronics.