Spin-orbit torques and magnetization switching in W/Co2FeAl/MgO structures

摘要

Magnetization switching by current induced spin-orbit torques (SOTs) in heavy metal/ ferromagnetic metal/oxide structures is of great research interest due to its potential applications in the field of low power consumption spintronic devices. Here, we study the Slonczewski-like and the field-like SOT effective fields in beta-W/Co2FeAl/MgO structures showing perpendicular magnetic anisotropy (PMA). We characterize the SOT effective fields using harmonic Hall voltage measurements and we point out the essential role of the planar Hall effect corrections. We estimate that for bulk beta-W an effective spin Hall angle as large as 0.3 +/- 0.03 and a spin diffusion length of 2.2 +/- 0.3 nm. Moreover, we demonstrate SOT-induced magnetization switching for charge current densities of the order of 10(6) A cm(-2).