“Current-induced switching of perpendicularly-magnetized magnetic layers using spin torque from the spin Hall effect.” L. Q. Liu, O. J. Lee, T. J. Gudmundsen, D. C. Ralph and R. A. Buhrman. Phys. Rev. Lett. 109, 096602 (2012). https://doi.org/10.1103/PhysRevLett.109.096602