Local control of magnetic interface effects in chiral Ir|Co|Pt multilayers using Ga+ ion irradiation

In this work we investigate local tuning of the iDMI and perpendicular magnetic anisotropy (PMA) using focused Ga+ ion beam irradiation, in an Ir vertical bar Co vertical bar Pt multilayer system. We show that the magnitude of the interface contribution to both effects can be significantly reduced by the irradiation with Ga+ ions. This leads to a reduction by a factor of 2 of the domain wall energy density, while still preserving the Neel character of the domain walls. Hence, we postulate that Ga+ ion irradiation is an effective way to locally reduce the energy barrier for skyrmion nucleation, providing a novel pathway for targeted skyrmion nucleation in racetrack type devices.