Fabrication and simulation of nanostructures for domain wall magnetoresistance studies on nickel

We report the use of electron beam lithography and a bilayer liftoff process to fabricate magnetic Ni nanostructures with constriction widths in the range of 22-41 nm. The structures fabricated correspond to the nanobridge geometry. Reproducibility and control over the final nanostructure geometry were observed when using the fabrication process introduced, these two qualities are important in order to carry out a more systematic analysis of domain wall magnetoresistance (DWMR). On the other hand, micromagnetic simulations of structures with the nanobridge geometry were carried out using not only the dimensions of the fabricated nanostructures but also smaller dimensions thought to be achievable with further optimization of the fabrication process. It was found that domain walls with a reduced length of 42.5 nm can be obtained using the nanobridge geometry. Furthermore, the anisotropic magnetoresistance (AMR) effect was calculated numerically and it was found to be smaller than the DWMR, this makes the nanobridge geometry a good candidate for future measurements of the magnetoresistive effect due to domain wall scattering.