Magnetic vortex-antivortex pairs in the magnetic stripe domain pattern: magnetization reversal and topology.

Bloch points and magnetic vortex-antivortex pairs are key actors in the magnetization reversal process of weak perpendicular anisotropy magnetic multilayers [1]. Bifurcations within the parallel stripe domain pattern act as nucleation sites for Bloch points at the onset of magnetization reversal and serve as guided paths for the subsequent propagation of vortex-antivortex pairs within the sample. In this work, we will present the analysis of topological charge transformations during the nucleation/propagation process based on micromagnetic simulations of NiFe/NdCo/NiFe multilayers and experimental 3D magnetization maps obtained from X-ray vector magnetic tomography of NiFe/NdCo/NiFe trilayers [2,3]. The signature of vortex-antivortex propagation in magnetotransport measurements taken during the magnetization reversal of NdCo and NiFe/NdCo/NiFe trilayers will also be discussed.

[1] A. Hierro-Rodriguez et al. Appl. Phys. Lett. 110 (2017) 262402.
[2] A. Hierro-Rodriguez et al. J. Synchr. Rad. 25 (2018) 1144
[3] A. Hierro-Rodriguez et al. Submitted (2020)