Magnetization Reversal of Individual Three Dimensional (3D) Fe-Co Nanostructures

Three dimensional (3D) magnetic nanostructures are promising for future magnetic memory and sensing applications, in particular since more complex magnetic configurations become possible when expanding 2D nanomagnets to the third dimension. In [1,2], we have employed focused electron beam induced deposition (FEBID) to grow 3D nanomagnets in combination with a micro-Hall sensor acting as substrate and high-resolution detection device of small magnetic stray fields. We find that the magnetisation reversal propagates by multi-domain switching scenarios. In this presentation, firstly, systematic measurements of the magnetic stray fields of Fe-Co nano-cubes and -trees as a function of temperature and magnetic field applied at different angles, will be reported. Secondly, in order to gain further insights in the hysteresis loops, (irreversible) magnetic interaction effects and coercivity distributions, first-order-reversal curves (FORC) of these 3D nanomagnets supported by simulations of a simple macro-spin model, will be shown. Finally, an outlook to the future design of such structures towards the realization of 3D artificial spin ice architectures will be given. [1] L.Keller et al., Sci. Rep. 8 , 6160 (2018). [2] M. Al Mamoori et al., Materials 11, 289 (2018).