Control over the domain wall (DW) dynamics in small magnetic structures is highly sought-after for technological applications in information storage and processing. To address this issue, we use a novel approach for trapping and manipulating domain walls based on artificial domain structures created by low-dose FIB irradiation. This scheme allows us to tune sample parameters such as local anisotropy, domain geometry and domain wall location, which may be used to tailor domain wall dynamics in magnetic nanostructures.

Magnetic properties of Ni₈₁Fe₁₉ /Au bilayers were investigated as a function of Ga⁺ ion dose and Ni₈₁Fe₁₉ thickness by means of focused magneto-optical Kerr effect (MOKE) magnetometry. It was found that magnetic properties such as coercivity, remanence ratio and hard axis anisotropy field could be tuned. Possible reasons for the change in magnetic properties were investigated using Monte-Carlo simulations to provide information on layer intermixing and Ga⁺ implantation. Moreover, X-ray reflectivity measurements give experimental evidence on intermixing and roughening in the samples.

We will also present primary field and current driven DW measurements on nanowires containing artificial domain structures. Control over the depinning field is achieved by varying the irradiated dose which tunes the coercivity of the irradiated wire section. Furthermore, by local FIB irradiation, artificial domain structures with different geometry and internal structure will be used to optimise the critical currents for current induced domain wall motion and to gain an understanding over the dynamics of propagating domain walls.