Current induced magnetization switching of thick antiferromagnet and ferromagnet by Seeded Spin-Orbit Torque*

One of the most exciting quests in spintronics is the discovery of more efficient current-induced torques for setting distinct magnetic states. In this regard, the well-established spin-orbit torque switching of magnetization has huge scientific and technological impact. However, short spin-diffusion lengths make it possible to switch only thin magnetic layers which, therefore, typically suffer from a lack of thermal stability. Here we report a novel Seeded Spin-Orbit Torque which sets the magnetic states of even thick layers of the chiral kagome antiferromagnet Mn₃Sn. This mechanism involves setting the orientation of the antiferromagnetic domains in a thin region at the interface of the Mn₃Sn with a heavy metal layer. This interface region seeds the resulting spin texture of the entire layer, and thereby overcomes the thickness limitation of conventional spin-orbit torques. Further, we show that this Seeded Spin-Orbit Torque switches efficiently a thick ferromagnet too. The current-induced Seeded Spin-Orbit Torque switching mechanism provides a path to the development of highly efficient and thermally stable spintronic devices.