Modeling magnetic-field-induced domain wall propagation in modulated-diameter cylindrical nanowires

TL;DR

This paper provides a theoretical analysis of how magnetic fields influence domain wall propagation in modulated-diameter cylindrical nanowires, combining numerical simulations and analytical modeling to inform nanowire design.

Contribution

It introduces a simple analytical scaling law linking domain wall depinning fields to diameter modulation slopes, aiding experimental and device design.

Findings

Pinning of domain walls near diameter modulations quantified

Depinning field proportional to modulation slope

Analytical model aligns with numerical simulations

Abstract

Domain wall propagation in modulated-diameter cylindrical nanowires is a key phenomenon to be studied with a view to designing three-dimensional magnetic memory devices. This paper presents a theoretical study of transverse domain wall behavior under the influence of a magnetic field within a cylindrical nanowire with diameter modulations. In particular, domain wall pinning close to the diameter modulation was quantified, both numerically, using finite element micromagnetic simulations, and analytically. Qualitative analytical model for gently sloping modulations resulted in a simple scaling law which may be useful to guide nanowire design when analyzing experiments. It shows that the domain wall depinning field value is proportional to the modulation slope.