Efficient spin-pumping and spin-to-charge conversion in epitaxial Mn$_3$Sn(0001) noncollinear antiferromagnetic films

TL;DR

This study demonstrates that epitaxial Mn$_3$Sn(0001) films exhibit efficient spin current generation and spin-to-charge conversion, making them promising for advanced spintronic devices due to their high spin Hall angle and conductivity.

Contribution

The paper provides the first systematic investigation of spin transport and conversion in epitaxial Mn$_3$Sn(0001) films, revealing high efficiency and potential for spintronic applications.

Findings

Spin Hall angle of 0.9% at room temperature.

Spin diffusion length exceeds 15 nm at room temperature.

High spin-mixing conductance and interfacial spin transparency in heterostructures.

Abstract

The generation and control of spin currents are crucial for advancing next-generation spintronic technologies. These technologies depend on materials capable of efficiently sourcing and interconverting spin and charge currents, while overcoming some limitations associated with conventional ferromagnets and heavy metals. Kagome topological antiferromagnetic Weyl semimetals, such as Mn$_3$Sn, present unique advantages owing to their distinct magnetic order and significant Berry curvature-driven transport phenomena. In this study, we systematically investigate spin current generation and spin-to-charge conversion phenomena in epitaxial (0001)-oriented Mn$_3$Sn thin films. Our findings reveal a spin Hall angle of 0.9$\%$ and a nearly isotropic in-plane spin Hall conductivity of 44.4~($\hbar$/e) $\Omega^{-1}$.cm$^{-1}$ at room temperature, originating from a combination of intrinsic and extrinsic contributions, as discussed in light of first-principle calculations. Furthermore, in Mn$_3$Sn(0001)/Ni$_{81}$Fe$_{19}$ heterostructures, we observe a high spin-mixing conductance of 28.52 nm$^{-2}$ and an interfacial spin-transparency of approximately 72$\%$. Notably, we also find that the spin diffusion length in Mn$_3$Sn(0001) epitaxial films exceeds 15 nm at room temperature. Our results highlight the potential of the topological Weyl noncollinear antiferromagnet Mn$_3$Sn as an efficient material for spin transport and conversion in prospective spintronic applications.