Tuning the perpendicular magnetic anisotropy, spin Hall switching current density and domain wall velocity by submonolayer insertion in Ta / CoFeB / MgO heterostructures

Abstract

By submonolayer insertion of Au, Pt, or Pd into Ta / CoFeB / MgO / Ta heterostructures we tune the perpendicular magnetic anisotropy and the coercive field of the ferromagnetic layer. We demonstrate that this has a major influence on the spin Hall switching current density and its dependence on the external magnetic field. Despite a rather small effective spin Hall angle of ${\theta }_{\mathrm{SH}}\approx -0.07$, we obtain switching current densities as low as $2\times 10^{10}$ A/m${}^2$ with a 2 Å Au interlayer. We find that the Dzyaloshinskii-Moriya interaction parameter $D$ is reduced with Au or Pd interlayers, and the perpendicular anisotropy field is reduced by an order of magnitude with the Pd interlayer. The dependence of the switching current density on the current pulse width is quantitatively explained with a domain wall nucleation and propagation model. Interface engineering is thus found to be a suitable route to tailor the current-induced magnetization switching properties of magnetic heterostructures.

5 pages, 5 figures

References in corpus (3)

• Enhancement of the Anti-Damping Spin Torque Efficacy of Platinum by Interface Modification
• Temperature dependence of the spin Hall angle and switching current in the nc-W(O)/CoFeB/MgO system with perpendicular magnetic anisotropy
• Phase diagram and optimal switching induced by spin Hall effect in a perpendicular magnetic layer