Domain wall damped harmonic oscillations induced by curvature gradients in elliptical magnetic nanowires

TL;DR

This paper investigates how curvature gradients in elliptical magnetic nanowires influence domain wall dynamics, revealing curvature-induced pinning and damped harmonic oscillations under external stimuli, which are crucial for spintronic applications.

Contribution

It demonstrates that curvature gradients induce effective fields that pin domain walls and cause damped harmonic oscillations, advancing understanding of DW behavior in curved nanowires.

Findings

Curvature gradients induce pinning of domain walls near maximum curvature.

Below a threshold, DW exhibits damped harmonic oscillations.

Above the threshold, DW moves with oscillatory translation.

Abstract

Understanding the domain wall (DW) dynamics in magnetic nanowires (NW) is crucial for spintronic-based applications demanding the use of DWs as information carriers. This work focuses on the dynamics of a DW displacing along a bent NW with an elliptical shape under the action of spin-polarized electric currents and external magnetic fields. Our results evidence that a curvature gradient induces an exchange-driven effective tangential field responsible for pinning a DW near the maximum curvature point in a NW. The DW equilibrium position depends on the competition between the torques produced by the external stimuli and the curvature-induced effective fields. When the external stimuli are below a certain threshold, the DW follows a damped harmonic oscillation around the equilibrium position. Above this threshold, DW displaces along the NW under an oscillatory translational motion.