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In recent years magnetic skyrmions attracted great attention for the possibility to move them with low current density, their intrinsic stability and their robustness against defects and edge roughness compared to other magnetic textures. For applications, it is very important to be able to influence the behaviour of skyrmions locally. In this article, we present an evaluation on the effects of FIB Ga+ irradiation on skyrmion motion in W/CoFeB/MgO thin films. The influence of FIB irradiation is evaluated both, in terms of modification of the skyrmion Hall angle and the skyrmion velocity. An overview of the effects of the pulsing parameters on the skyrmion motion, shows low influence of the pulses rise-time and an external magnetic field. In addition the analysis after the irradiation shows that it influences notably the dynamics of skyrmions. In the irradiated zone the speed and angle of motion of these magnetic textures are strongly reduced. [ABSTRACT FROM AUTHOR]

In this paper, we show the feasibility of tuning both the location of domain wall nucleation and the required nucleation field by changing the geometry of nanomagnets using shadowing effects. The perpendicular anisotropy is locally reduced by shadowing effects during sputter deposition. A 3-D model based on experimental measurements of fabricated nanomagnets has been developed. Experimental data from atomic force microscopy measurements and anisotropy measurements of fabricated Co/Pt-nanomagnets allow to realistically model the anisotropy and geometry of the nanomagnets. Micromagnetic simulations based on the developed 3-D model have been performed. It is shown that increasing the undercut in the resist decreases the switching field of the nanomagnets. By varying the tip geometry of the nanomagnet, the switching field can be further decreased, and subsequently, the nucleation point can be controlled, making this technique feasible for the use in perpendicular nanomagnetic logic circuitry. [ABSTRACT FROM AUTHOR]