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

## TL;DR

This study demonstrates how submonolayer insertion of Au, Pt, or Pd in Ta/CoFeB/MgO heterostructures can effectively tune magnetic anisotropy, switching current density, and domain wall velocity, enabling optimized spintronic device performance.

## Contribution

It introduces interface engineering via submonolayer insertion as a novel method to control magnetic and spintronic properties in heterostructures.

## Key findings

- Switching current densities as low as 2×10^10 A/m^2 achieved with Au interlayer.
- Dzyaloshinskii-Moriya interaction parameter D reduced by Au or Pd interlayers.
- Perpendicular anisotropy field decreased by an order of magnitude with Pd interlayer.

## 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 \AA{} 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.