We study deterministic magnetic reversal of a perpendicularly magnetized Co layer in a Co/MgO/Ta nano-square driven by spin Hall torque from an in-plane current flowing in an underlying Pt layer. The rate-limiting step of the switching process is domain-wall (DW) depinning by spin Hall torque via a thermally-assisted mechanism that eventually produces full reversal by domain expansion. An in-plane applied magnetic field collinear with the current is required, with the necessary field scale set by the need to overcome DW chirality imposed by the Dzyaloshinskii-Moriya interaction. Once Joule heating is taken into account the switching current density is quantitatively consistent with a spin Hall angle {\theta}SH≈ 0.07 for 4 nm of Pt.
@article{arxiv.1312.7301,
title = {Central role of domain wall depinning for perpendicular magnetization switching driven by spin torque from the spin Hall effect},
author = {O. J. Lee and L. Q. Liu and C. F. Pai and H. W. Tseng and Y. Li and D. C. Ralph and R. A. Buhrman},
journal= {arXiv preprint arXiv:1312.7301},
year = {2015}
}