  The generation of spin currents and their application to the manipulation of
magnetic states is fundamental to spintronics. Of particular interest are
chiral antiferromagnets that exhibit properties typical of ferromagnetic
materials even though they have negligible magnetization. Here, we report the
generation of a robust spin current with both in-plane and out-of-plane spin
polarization in epitaxial thin films of the chiral antiferromagnet Mn3Sn in
proximity to permalloy thin layers. By employing temperature-dependent
spin-torque ferromagnetic resonance, we find that the chiral antiferromagnetic
structure of Mn3Sn is responsible for an in-plane polarized spin current that
is generated from the interior of the Mn3Sn layer and whose temperature
dependence follows that of this layer's antiferromagnetic order. On the other
hand, the out-of-plane spin polarized spin current is unrelated to the chiral
antiferromagnetic structure and is instead the result of scattering from the
Mn3Sn/permalloy interface. We substantiate the later conclusion by performing
studies with several other non-magnetic metals all of which are found to
exhibit out-of-plane polarized spin currents arising from the spin swapping
effect.
