Effect of interfacial intermixing on spin-orbit torque in Co/Pt bilayers

Using the first-principles non-equilibrium Green’s function technique [1] with supercell disorder averaging, we study the influence of interfacial intermixing on the spin-orbit torque in Co/Pt (111) bilayers. The interlayer distances are optimized, several models of intermixing are considered, and atomic potentials in the intermixed layers are obtained using the coherent potential approximation. The magnitude and thickness dependence of the damping-like torque are similar to earlier results for the Co/Pt (001) interface [1,2] and rather insensitive to intermixing. In contrast, the field-like torque, which is small in the case of an ideal interface, is dramatically enhanced by intermixing.

[1] K. D. Belashchenko, A. A. Kovalev, and M. van Schilfgaarde, Phys. Rev. Mater. 3, 011401 (2019).
[2] K. D. Belashchenko, A. A. Kovalev, and M. van Schilfgaarde, arXiv:1908.02680.