Tailoring the nucleation of domain walls along multi-segmented cylindrical nanoelements

TL;DR

This paper explores how the magnetization reversal and domain wall nucleation in three-segment cylindrical nanoelements can be controlled by geometric and material modifications, enabling advanced magnetic device functionalities.

Contribution

It demonstrates the ability to tailor domain wall nucleation and movement in hybrid nanoelements through geometric design, offering new ways to control magnetic states for device applications.

Findings

Domain wall nucleation can be localized near the center or tips of the nanoelements.

Geometry and material variations influence the nucleation field and sequence.

Coherent domain wall movement can be achieved in different directions by design.

Abstract

The magnetization reversal of three-segment cylindrical nanoelements comprising of alternating nanowire and nanotube sections is investigated by means of Monte Carlo simulations. Such nanoelements may feature a three-state behaviour with an intermediate plateau in the hysteresis curve due to a metastable pinning of the domain walls at the wire-tube interfaces. It turns out that vortex as well as transverse domain walls contribute to the magnetization reversal. By varying the geometric parameters, the sequence, or the material of the elements the nucleation location of domain walls, as well as their nucleation field, can be tailored. Especially interesting is the novel possibility to drive domain walls coherently in the same or in opposite directions by changing the geometry of the hybrid nanoelement. This important feature adds additional flexibility to the construction of logical devices based on domain wall movement. Another prominent outcome is that domain walls can be nucleated near the centre of the element and then traverse to the outer tips of the cylindrical structure when the applied field is increased, which also opens the possibility to use these three-segment nanoelements for the field induced delivery of domain walls as substitutes for large nucleation pads.