Unconventional spin-orbit torques in IrO₂ based devices

Spin–orbit torques (SOTs) generated by a spin current are key to magnetic switching in spintronic applications. The polarization of the spin current dictates the direction of switching required for energy-efficient devices. Conventionally, the polarizations of these spin currents are restricted to be along a certain direction due to the symmetry of the material allowing only for efficient in-plane magnetic switching. Unconventional spin–orbit torques arising from novel spin current polarizations, however, have the potential to switch other magnetization orientations such as perpendicular magnetic anisotropy, which is desired for higher density spintronic-based memory devices. Here, we demonstrate unconventional SOTs in IrO₂ based devices using thin film engineering techniques and heterostructure design.¹ We show field-free switching of a PMA using out-of-plane SOTs in IrO₂ and relate the crystal symmetry to the symmetry of the SOTs. These results offers a new approach to discovering unconventional SOTs in materials with higher symmetry.

¹ M.V. Patton, et al. (2023) Adv. Mater. 35, 2301608