Chirality-Dependent Domain Wall Splitting and Recombination in Ferromagnetic Nanostructure with an Anti-dot

The domain wall (DW) motion in ferromagnetic nanostructures is an interesting research area both for fundamental understanding and for spintronic device applications. In this work, we have investigated the effect of vortex domain wall (VDW) chirality on the splitting and recombination process in ferromagnetic nanowire with an anti-dot. A tail-to-tail VDW initially splits into two transverse DWs (TDW) and recombination of TDWs leads to either 360° DW formation or annihilation. We have observed that the chirality of VDW affects the magnetization reversal within the nanowire where a clockwise VDW results in 360° DW formation via recombination. However, an anticlockwise VDW annihilates the two TDWs. This chirality-dependent recombination is observed only above a particular anti-dot width (> 100 nm). When the anti-dot width is below 100 nm, the splitting and recombination process is independent of the chirality of the VDWs. Interestingly, for head-to-head VDW, a similar behavior is observed, however, with an opposite chirality leading to a cross-symmetry. The spin configuration around the pinning site in the nanowire plays a vital role in DW pinning and reversal mechanism. The TDW in the branch can proceed or gets obstructed depending on the relative orientation between the DW chirality and magnetization in the nanowire and thus dictates the formation of 360° DW.