  Current induced spin-orbit torques driven by the conventional spin Hall
effect are widely used to manipulate the magnetization. This approach, however,
is nondeterministic and inefficient for the switching of magnets with
perpendicular magnetic anisotropy that are demanded by the high-density
magnetic storage and memory devices. Here, we demonstrate that this limitation
can be overcome by exploiting a magnetic spin Hall effect in noncollinear
antiferromagnets, such as Mn3Sn. The magnetic group symmetry of Mn3Sn allows
generation of the out-of-plane spin current carrying spin polarization induced
by an in-plane charge current. This spin current drives an out-of-plane
anti-damping torque providing deterministic switching of perpendicular
magnetization of an adjacent Ni/Co multilayer. Compared to the conventional
spin-orbit torque devices, the observed switching does not need any external
magnetic field and requires much lower current density. Our results demonstrate
great prospects of exploiting the magnetic spin Hall effect in noncollinear
antiferromagnets for low-power spintronics.
