Field-Free Switching of Perpendicular Magnetization by Anisotropic Spin Hall Effect in Mn₃Ir

Manipulation of the magnetization by spin-orbit torque (SOT) stands as a crucial advancement in spintronics due to its merits in energy-efficient and high-speed operation. However, the conventional SOT devices involving a heavy metal/ferromagnet cannot deterministically switch the perpendicularly magnetized ferromagnet without an external magnetic field, which hinders its practical implementation. Here, room temperature field-free switching for perpendicularly magnetized ferromagnets is demonstrated using spin currents with the out-of-plane spin polarization induced by noncollinear antiferromagnets L1(2)-Mn3Ir. Both in-plane and out-of-plane spin polarizations are observed, and the tilting angle of the spin polarization is estimated to be approximate to 10 degrees. The spin Hall conductivity of out-of-plane spin is 1.43 x 10(4) h/2e.Omega(-1)m(-1), which is the largest among several 2D and antiferromagnetic materials, including WTe2, RuO2, and Mn3GaN. Furthermore, field-free SOT switching is demonstrated with an ns-current pulse, and the current density is comparable with the reported values of the field-assisted pulse switching. This work paves the way for employing noncollinear antiferromagnets for wafer-scale spintronic device applications.