Domain wall pinning in FeCoCu bamboo-like nanowires

TL;DR

This study investigates how periodic diameter modulations in FeCoCu nanowires influence domain wall pinning and propagation, using Magnetic Force Microscopy and micromagnetic simulations to reveal controllable pinning behavior.

Contribution

It demonstrates the effect of diameter modulations on domain wall pinning and shows how external magnetic fields can control pinned domain walls in FeCoCu nanowires.

Findings

Periodic diameter modulations cause domain wall pinning.

Metastable magnetic states can be observed with refined MFM imaging.

External magnetic fields can control the position of pinned domain walls.

Abstract

The pinning effect of the periodic diameter modulations on the domain wall propagation in FeCoCu individual nanowires is determined by Magnetic Force Microscopy, MFM. A main bistable magnetic configuration is firstly concluded from MFM images characterized by the spin reversal between two nearly single domain states with opposite axial magnetization. Complementary micromagnetic simulations confirm a vortex mediated magnetization reversal process. A refined MFM imaging procedure under variable applied field allows us to observe metastable magnetic states where the propagating domain wall is pinned at certain positions with enlarged diameter. Moreover, it is demonstrated that in some atypical nanowires with higher coercive field it is possible to control the position of the pinned domain walls by an external magnetic field.